Filtreyi doğru ekleseydim, çağrı merkezinden gelen mesajları kaçırmazdım.

Ekleseydim means if I had added.

It breaks down like this:

• ekle- = add
• -se / -sa = conditional marker, roughly if
• -ydi / -ydı = past layer
• -m = I

So:

• ekle-sey-di-m → if I had added

In sentences like this, Turkish often uses -seydi / -saydı in the if-clause to express a past unreal condition:

• Gelseydim = if I had come
• Söyleseydin = if you had said
• Ekleseydim = if I had added

This is the Turkish equivalent of English if I had done...

In this sentence, kaçırmazdım is the result part of a past unreal conditional.

It comes from:

• kaçırmak = to miss, let slip, fail to catch
• kaçırmazdım = I would not miss / I wouldn’t have missed

The form is:

• kaçır-maz-dı-m

Here:

• -maz = negative aorist-style form
• -dı = past
• -m = I

In conditional sentences, this kind of form often corresponds to English would / wouldn’t have:

• Ekleseydim, kaçırmazdım
  = If I had added it, I wouldn’t have missed it

So even though it is not built exactly like English, this is the normal Turkish way to express that kind of counterfactual result.

Because Turkish uses different verbs for different meanings of miss.

• kaçırmak = to miss in the sense of fail to catch, fail to notice, fail to attend
• özlemek = to miss in the emotional sense of longing for someone or something

So:

• mesajı kaçırmak = to miss a message
• otobüsü kaçırmak = to miss the bus
• fırsatı kaçırmak = to miss an opportunity

But:

• Annemi özledim = I missed my mother
• Türkiye’yi özledim = I missed Turkey

Here we are talking about failing to notice or receive messages, so kaçırmak is the correct verb.

Because filtreyi is a definite direct object.

• filtre = filter
• filtreyi = the filter

The ending -yi is the accusative case. Turkish often marks a direct object with the accusative when it is specific or definite.

So:

• Filtre ekledim = I added a filter
• Filtreyi ekledim = I added the filter

In your sentence, it sounds like a specific filter is being referred to, so filtreyi is natural.

Also note the y is just a buffer consonant:

• filtre + i → filtreyi

Because mesajları is also a definite direct object.

It is:

• mesajlar = messages
• mesajları = the messages

Here the phrase çağrı merkezinden gelen mesajları means the messages coming from the call center, which is a specific group of messages, so the accusative is used.

A useful point: mesajları can sometimes look ambiguous, because the same form can also mean his/her messages in other contexts. But here, with no possessor intended, it clearly means the messages as the direct object.

Here doğru works like an adverb and means correctly or properly.

So:

• doğru eklemek = to add correctly / to set up correctly

Turkish often uses the same word where English would use either an adjective or an adverb. There is no separate -ly ending like in English.

Compare:

• doğru cevap = correct answer
• doğru yaptım = I did it correctly

So in your sentence:

• Filtreyi doğru ekleseydim...
  = If I had added/set up the filter correctly...

Literally, it means coming from the call center.

Breakdown:

• çağrı merkezi = call center
• çağrı merkezinden = from the call center
• gelen = coming / that comes / that came

So:

• çağrı merkezinden gelen mesajlar
  = messages coming from the call center = more naturally in English, messages from the call center

This is a very common Turkish structure:

• [noun + participle] + noun

Examples:

• okuldan gelen mektup = the letter coming from school
• dün gördüğüm adam = the man I saw yesterday
• masada duran kitap = the book standing/lying on the table

Here gelen is a participle modifying mesajları.

Because çağrı merkezi is a noun compound.

The dictionary form is already:

• çağrı merkezi = call center

That final -i is part of the compound structure. When you add a case ending, Turkish attaches it after that:

• çağrı merkezi = call center
• çağrı merkezine = to the call center
• çağrı merkezinde = at the call center
• çağrı merkezinden = from the call center

So merkezinden is not random; it comes from the compound form çağrı merkezi.

This is very common:

• otobüs durağı = bus stop
• otobüs durağında = at the bus stop

Because Turkish does not need eğer if the verb already has the conditional ending -se / -sa.

So:

• Filtreyi doğru ekleseydim... already means If I had added the filter correctly...

You can add eğer for emphasis:

• Eğer filtreyi doğru ekleseydim, çağrı merkezinden gelen mesajları kaçırmazdım.

But it is optional. In everyday Turkish, it is very common to leave it out.

Because Turkish usually leaves out subject pronouns when the verb ending already shows the person.

In this sentence, both verbs show I:

• ekleseydi-m = if I had added
• kaçırmazdı-m = I wouldn’t have missed

So ben is unnecessary unless you want emphasis or contrast.

For example:

• Ben filtreyi doğru ekleseydim, kaçırmazdım.
  = If I had added it correctly, I wouldn’t have missed it
  with extra emphasis on I

Turkish is often a pro-drop language in this way.

Yes. It is a classic past counterfactual / unreal conditional.

It means the speaker is talking about something that did not happen in the past, and about a result that also did not happen because of that.

Pattern:

• if-clause: -seydi / -saydı
• main clause: often -rdı / -mazdı

So here:

• Filtreyi doğru ekleseydim = If I had added the filter correctly
• ...mesajları kaçırmazdım = ...I wouldn’t have missed the messages

Another example:

• Daha erken çıksaydım, otobüsü kaçırmazdım.
  = If I had left earlier, I wouldn’t have missed the bus.

Yes. Turkish word order is flexible, although the version you have is very natural.

Current order:

• Filtreyi doğru ekleseydim, çağrı merkezinden gelen mesajları kaçırmazdım.

This is natural because it gives the condition first and the result second.

You could rearrange parts for emphasis, for example:

• Çağrı merkezinden gelen mesajları filtreyi doğru ekleseydim kaçırmazdım.

But that sounds more marked and would usually be used only in a particular context.

So for learners, the safest takeaway is:

• this sentence order is normal
• Turkish allows movement for emphasis
• the verb usually stays near the end

It can cover both, depending on context.

The participle -en / -an often gives a broad relative-clause meaning:

• gelen mesajlar = messages that come / are coming / came

In practice, English translation depends on what sounds natural in context.

So:

• çağrı merkezinden gelen mesajlar
  can be understood as
  messages from the call center
  or more literally
  messages coming from the call center

English usually prefers the smoother version, but the Turkish structure itself is very normal and broad.

Yes, you could, but it is heavier and less natural in many everyday contexts.

Compare:

• Filtreyi doğru ekleseydim = If I had added the filter correctly
• Filtreyi doğru bir şekilde ekleseydim = If I had added the filter in a correct way

The longer version is not wrong, but Turkish often prefers the simpler adverb-like use of doğru.

So doğru ekleseydim is the more natural choice here.