Служба поддержки приняла претензию.

Because the subject, служба, is a feminine singular noun.

In the past tense, Russian verbs agree with the subject in gender and number:

• он принял = he accepted
• она приняла = she accepted
• оно приняло = it accepted
• они приняли = they accepted

Even though служба поддержки means support service or customer support, the head noun is служба, which is feminine, so the verb is приняла.

Because поддержки is in the genitive case. Russian often uses this pattern to express something like X of Y.

So:

• служба = service
• поддержка = support
• служба поддержки = service of support, which naturally means support service

This is a very common Russian structure:

• центр города = city center
• чашка чая = cup of tea
• отдел продаж = sales department

So поддержки is not the subject here. It is dependent on служба.

Because it is the direct object, so it goes into the accusative case.

Претензия is a feminine noun ending in -я, and for many feminine nouns like this, the accusative singular changes -я to -ю:

• претензия → претензию
• станция → станцию
• лекция → лекцию

So:

• претензия = nominative form
• претензию = accusative form, used because it is what was accepted

Претензия usually means a claim, complaint, or formal grievance. It often sounds more formal or official than жалоба.

Very roughly:

• жалоба = complaint in a general sense
• претензия = complaint/claim, often in a business, legal, or customer-service context

So in this sentence, претензию suggests something like a formal customer complaint or claim that the support service accepted for processing.

Because приняла is perfective, and it presents the action as completed: the support service accepted the complaint.

Compare:

• Служба поддержки приняла претензию.
  = The support service accepted the complaint.
  Focus: the result happened.

• Служба поддержки принимала претензию.
  = The support service was accepting the complaint / used to accept complaints.
  Focus: process, duration, or repeated action

In a simple statement about a completed event, Russian normally uses the perfective verb принять → приняла.

Yes. Russian word order is more flexible than English because case endings show the grammatical roles.

The neutral order here is:

• Служба поддержки приняла претензию.

But you could also say:

• Претензию приняла служба поддержки.
• Служба поддержки претензию приняла.

These versions are still understandable, but the emphasis changes:

• starting with претензию highlights the complaint
• ending with приняла can emphasize the fact that it was accepted

For a learner, the original order is the safest and most neutral.

Russian has no articles. It does not use words like the or a/an.

So Служба поддержки приняла претензию can mean:

• The support service accepted the complaint
• A support service accepted a complaint

Which one is intended depends on context. In many real situations, context makes it clear that English would use the.

Yes, very natural. It commonly means:

• support service
• customer support
• help desk
• support department

It is especially common in business, technical, and customer-service contexts.

Examples:

• обратиться в службу поддержки = to contact customer support
• служба поддержки клиентов = customer support service
• ответ службы поддержки = reply from support

So this sentence sounds normal and natural in a formal or semi-formal context.

The stress is:

• слу́жба
• подде́ржки
• приняла́
• прете́нзию

A rough pronunciation guide:

• слу́жба = SLOOZH-ba
• подде́ржки = pad-DYERZH-kee
• приняла́ = pree-nee-LA
• прете́нзию = pre-TEN-zee-yu

Stress matters in Russian, so it is worth learning words together with their stressed syllables.

Sometimes in context, yes, but приняла most directly means accepted, not just received.

Compare:

• принять претензию = to accept a complaint/claim
• получить претензию = to receive a complaint/claim

So if the meaning is that customer support officially took it up or registered it, accepted is better. If the meaning is only that they got it, received would be better in English, but Russian would more likely use получила.