Ten spyte van die fout bly die betaaltydperk dieselfde.

Yes. Ten spyte van is a fixed expression meaning despite or in spite of.

So:

• Ten spyte van die fout = Despite the error

You should learn it as a whole phrase. Even though the individual words have older or more formal origins, modern learners usually just treat ten spyte van as one unit.

A near-synonym is ondanks:

• Ten spyte van die fout ...
• Ondanks die fout ...

Both are correct, though ten spyte van may feel a little more formal or set-phrase-like.

This is because Afrikaans follows the verb-second rule in main clauses.

The sentence begins with the fronted phrase:

• Ten spyte van die fout

Once that phrase is placed first, the finite verb must come next:

• Ten spyte van die fout bly ...

After that comes the subject:

• Ten spyte van die fout bly die betaaltydperk dieselfde.

Compare the more neutral order:

• Die betaaltydperk bly dieselfde ten spyte van die fout.

Both are correct, but when you move Ten spyte van die fout to the front for emphasis, bly must move into second position.

Here bly means remain.

In other contexts, bly can mean stay or live, depending on the sentence:

• Ek bly in Kaapstad. = I live in Cape Town.
• Bly hier! = Stay here!
• Dit bly dieselfde. = It remains the same.

In your sentence, bly is a linking verb connecting the subject to its state:

• die betaaltydperk → dieselfde

So the sense is the payment period remains the same.

Because in Afrikaans, dieselfde meaning the same is normally written as one word.

Examples:

• Ons het dieselfde probleem. = We have the same problem.
• Dit bly dieselfde. = It remains the same.

It is best to memorize dieselfde as a single word meaning the same.

Betaaltydperk is a compound noun:

• betaal = pay / payment
• tydperk = period / term

Together:

• betaaltydperk = payment period / pay period

Afrikaans, like Dutch and German, very often writes compound nouns as one word. English often uses two words where Afrikaans prefers one.

More examples:

• hospitaalrekening = hospital bill
• werksure = working hours
• bankrekening = bank account

So betaaltydperk is completely normal Afrikaans spelling.

Die is the definite article in Afrikaans, meaning the.

So:

• die fout = the error
• die betaaltydperk = the payment period

A useful thing for English speakers is that Afrikaans does not have separate words for the based on gender, like German does. Die is used very broadly for singular and plural definite nouns.

Examples:

• die man = the man
• die vrou = the woman
• die kinders = the children

So in your sentence, both nouns are definite, which is why both take die.

Because Afrikaans does not have the kind of case endings that languages like German use.

After van you simply get:

• van die fout = of the error / despite the error in this expression

The noun fout stays the same. English speakers often find this nice and simple: Afrikaans nouns usually do not change form because of case.

In this sentence, dieselfde functions like a predicative adjective/complement after the linking verb bly.

Structure:

• die betaaltydperk = subject
• bly = linking verb
• dieselfde = complement describing the subject

So it works like:

• The payment period remains the same

Compare:

• Die tydperk is lank. = The period is long.
• Die tydperk bly dieselfde. = The period remains the same.

So dieselfde is telling you what state the payment period remains in.

Yes, absolutely.

That version is also correct:

• Die betaaltydperk bly dieselfde ten spyte van die fout.

The difference is mainly emphasis and style.

• Ten spyte van die fout bly die betaaltydperk dieselfde.
  • emphasizes the contrast first: despite the error
• Die betaaltydperk bly dieselfde ten spyte van die fout.
  • starts with the main topic: the payment period

Both are natural Afrikaans.

Usually, no comma is required:

• Ten spyte van die fout bly die betaaltydperk dieselfde.

Afrikaans does not require a comma here just because the sentence starts with a prepositional phrase.

That said, a writer might sometimes insert a comma for readability in longer or heavier sentences, but in a short sentence like this, leaving it out is the normal choice.

A rough guide for an English speaker:

• bly sounds roughly like blay, but with the Afrikaans y sound, which is not exactly the same as English ay
• spyte sounds roughly like spay-tuh or spite-uh, depending on how carefully someone speaks

A few notes:

• y in Afrikaans often sounds a bit like the vowel in Dutch ij, not exactly like any single English vowel
• the final -e in spyte is a weak vowel, like uh

If you are learning pronunciation, it is best to hear native audio, because spellings like bly can be misleading if you read them with English sound rules.

Often, yes—at least slightly.

Both mean despite, but they can feel a little different in tone:

• ten spyte van = a set phrase, often slightly more formal or emphatic
• ondanks = concise and very common in writing

So these are both good:

• Ten spyte van die fout bly die betaaltydperk dieselfde.
• Ondanks die fout bly die betaaltydperk dieselfde.

Neither is wrong. The choice is mostly about style and preference.