Ako mi se mobitel pokvari, neću ti se moći javiti.

In Croatian, after ako when you mean a real future possibility, you usually use the present tense in the if-clause, not a future form.

So:

• Ako mi se mobitel pokvari... = If my phone breaks down...
• not something like Ako će mi se mobitel pokvariti... in normal usage here

This is very natural in Croatian. English often uses the same pattern too: If my phone breaks..., not If my phone will break.

Also, pokvari is from a perfective verb, so it refers to a single completed event in the future: the moment the phone stops working.

Mi is the unstressed dative form of ja and here it means to me or on me, but the most natural English interpretation is my.

So:

• Ako mi se mobitel pokvari literally means something like If the phone breaks on me / to me
• naturally: If my phone breaks down

This is a very common Croatian structure called the dative of possession/interest, where Croatian often uses a dative pronoun instead of a possessive adjective.

Compare:

• Pokvario mi se auto. = My car broke down.
• literally: The car broke down on me.

Because Croatian often does not need moj, tvoj, etc. when possession is already clear from the dative pronoun.

So:

• mi se mobitel pokvari already clearly means my phone breaks down
• moj mobitel is possible, but it would usually sound more emphatic or contrastive

For example:

• Ako mi se mobitel pokvari... = neutral, natural
• Ako se moj mobitel pokvari... = more like if my phone breaks (perhaps contrasting it with someone else’s)

The verb here is pokvariti se, which means to break down / stop working / become faulty.

That se is part of the verb. It does not mean itself in a literal English sense here.

Compare:

• pokvariti = to spoil something / to ruin something / to break something
• pokvariti se = to break down, to go wrong, to become faulty

So:

• Pokvario sam mobitel. = I broke the phone.
• Mobitel se pokvario. = The phone broke down.

In your sentence, se belongs to pokvari.

Because javiti se is another verb that normally includes se. It means things like:

• to get in touch
• to contact
• to call/message someone
• sometimes to report in or to make oneself heard from

So in this sentence:

• neću ti se moći javiti = I won’t be able to get in touch with you / contact you

Again, the se is just part of the verb javiti se.

Here javiti se means to contact someone, especially by phone or message.

Because the sentence mentions a phone, the most natural sense is:

• I won’t be able to call you
• I won’t be able to message you
• I won’t be able to get in touch with you

It does not necessarily mean only call in a narrow sense. It is broader: to reach out / make contact.

Also note the pattern:

• javiti se nekome = to contact someone
• ti is the dative pronoun meaning to you

Because javiti se takes the person contacted in the dative.

So:

• javiti se tebi = to contact you
• unstressed form: ti

Examples:

• Javit ću ti se kasnije. = I’ll contact you later.
• Nisam ti se mogao javiti. = I couldn’t get in touch with you.

This is different from English, where we just say contact you without showing case.

This part is built from several pieces:

• neću = I will not
• moći = be able
• javiti se = contact / get in touch
• ti = to you

So literally it is:

• I will not be able to contact you

More exactly:

• neću is the future of htjeti used as the normal future auxiliary
• moći stays in the infinitive after neću
• javiti also stays in the infinitive because it depends on moći
• se belongs to javiti

So the structure is basically:

• neću + moći + javiti se

In modern standard Croatian, the correct spelling is neću as one word.

The same applies to the other forms:

• neću
• nećeš
• neće
• nećemo
• nećete
• neće

These are the negative future forms built from htjeti.

Croatian has a special placement system for unstressed short words called clitics. Words like mi, ti, se, ću, sam, etc. usually go in a fixed position near the beginning of their clause.

That is why Croatian says:

• Ako mi se mobitel pokvari...
• ...neću ti se moći javiti.

not with the pronouns placed freely in any position.

For learners, it is often best to learn these combinations as natural chunks:

• mi se
• ti se
• neću ti se javiti
• javit ću ti se

You do not need to over-analyze every detail at first, but you should get used to the fact that these short forms usually come early and cluster together.

This is about aspect, which is very important in Croatian.

• kvariti se = imperfective
• pokvariti se = perfective

Here, pokvari is used because the sentence refers to a single completed event in the future: the phone ending up broken.

So:

• Ako mi se mobitel pokvari... = If my phone breaks down...
• Ako mi se mobitel kvari... would suggest if my phone is malfunctioning / keeps going wrong, which is a different meaning

Perfective present forms like pokvari often refer to future events in clauses like this.

Yes, Croatian word order is fairly flexible, although not completely free.

For example, these are all possible with slightly different emphasis:

• Ako mi se mobitel pokvari, neću ti se moći javiti.
• Ako se mi mobitel pokvari is not correct, because the clitics do not go in that order
• Ako mi se pokvari mobitel, neću ti se moći javiti. = also natural
• Neću ti se moći javiti ako mi se mobitel pokvari. = also natural

What usually stays stable is the clitic placement:

• mi se
• ti se

So the noun and larger phrase can move more easily than those short pronouns.

Yes, mobitel is very common and feels especially standard/natural in Croatian for mobile phone / cell phone.

You may also hear:

• telefon = phone
• mobitel = mobile phone

In this sentence, mobitel is a very natural choice because the idea is specifically a mobile phone you use to contact someone.

So:

• Ako mi se mobitel pokvari... sounds very normal
• Ako mi se telefon pokvari... is also possible, but it can be less specific depending on context

Not exactly.

• Neću ti se javiti. = I won’t contact you.
• Neću ti se moći javiti. = I won’t be able to contact you.

The version with moći adds the idea of lack of ability/opportunity, not unwillingness.

In your sentence, that matters because the reason is the broken phone. So moći is important: the speaker is not refusing; they simply may be unable to make contact.