Tā yǐjīng liánxì kèfú le, xiǎng wèn zěnme tuìhuò hé tuìkuǎn.

This is a very common Mandarin pattern.

已经 means already, and 了 here marks that the action is completed or that a new situation has occurred.
Together, 已经 ... 了 strongly emphasizes that something has already happened.

So:

• 她已经联系客服了 = She has already contacted customer service

You will often see this structure:

• 我已经吃了。 = I already ate / I’ve already eaten.
• 他已经到了。 = He has already arrived.

In many cases, Mandarin can use just one of them, but using both sounds very natural and clear.

Because 联系客服 is the whole verb-object phrase:

• 联系 = to contact
• 客服 = customer service

In Mandarin, sentence-final or clause-final 了 often comes after the entire action phrase, not immediately after the verb.

So:

• 她已经联系客服了

not usually:

• 她已经联系了客服 — this is also possible, but it puts 了 as a perfective marker directly after the verb.

Both can work, but they are slightly different in feel:

• 联系了客服 focuses more on the action being completed
• 联系客服了 often sounds more like the situation now is that she has contacted customer service

Both are natural.

联系 is a verb meaning to contact or to get in touch with.

In this sentence:

• 联系 客服 = contact customer service

It is a very common verb in formal and everyday Chinese:

• 请联系我。 = Please contact me.
• 我会联系他们。 = I’ll contact them.

It can also be used as a noun in other contexts, meaning connection or relation, but here it is clearly a verb.

Yes. 客服 is a very common shortened form of 客服人员 or 客户服务.

It usually means:

• customer service
• customer support
• sometimes a customer service representative

In online shopping, apps, and e-commerce, 联系客服 is extremely common and means contact customer service.

Examples:

• 请联系客服。 = Please contact customer service.
• 客服回复很快。 = Customer service replied quickly.

The subject is still understood to be 她.

Mandarin often omits repeated subjects when they are obvious from context. So this sentence is understood as:

• 她已经联系客服了，(她)想问怎么退货和退款。

In natural English, we often repeat the subject, but in Mandarin, leaving it out is very normal.

So the sentence flows like:

• She has already contacted customer service and wants to ask how to return the item and get a refund.

Yes, basically. 想问 literally means want to ask.

But in real usage, it can sound softer and more natural than a very direct ask. Depending on context, it can mean:

• wants to ask
• would like to ask
• is wondering

Examples:

• 我想问一下。 = I’d like to ask something.
• 他想问怎么操作。 = He wants to ask how to do it / He wants to know how to operate it.

So in your sentence, 想问怎么退货和退款 means she wants to ask about the method or process.

Here 怎么 means how or how to.

So:

• 怎么退货 = how to return goods
• 怎么退款 = how to get a refund / how to process a refund

In the sentence, 怎么 applies to both 退货 and 退款.

Mandarin often does this without repeating 怎么:

• 想问怎么退货和退款

This is like saying in English:

• want to ask how to return the item and get a refund

If you wanted to be more explicit, you could also say:

• 想问怎么退货，怎么退款。

But the original version is shorter and very natural.

They are related, but not identical.

• 退货 = return the goods / return the item
• 退款 = refund the money

So:

• 货 = goods, merchandise
• 款 = funds, money amount

In shopping situations, these are often mentioned together because returning an item and getting a refund are connected but technically different actions.

Examples:

• 我想退货。 = I want to return the item.
• 什么时候退款？ = When will the refund be issued?

和 means and.

So:

• 退货和退款 = returning the goods and getting a refund

This connects the two things she wants to ask about.

In many situations, Chinese could also use 还是, 或者, or just list things without a conjunction, but 和 is the straightforward and here.

It means how to return the goods and get a refund.

In English, refund is usually a noun or sometimes a verb, but in Chinese 退款 is a verb-object expression meaning refund money or to process a refund.

So the natural English understanding is:

• how to return the item and get a refund
• how to do a return and refund

Yes, it helps separate two related parts:

1. 她已经联系客服了
2. 想问怎么退货和退款

This is very common in Chinese: one clause gives the background, and the next clause gives the purpose or next action.

So the comma works a bit like:

• She has already contacted customer service, and she wants to ask...

Chinese punctuation is often used to break longer thoughts into clear chunks.

Yes, that is grammatically possible, but it changes the emphasis.

Original:

• 她已经联系客服了，想问怎么退货和退款。

This presents the action first, then the reason/purpose.

Your version:

• 她想问怎么退货和退款，所以已经联系客服了。

This presents the reason first, then says so she already contacted customer service.

Both make sense, but the original sounds more like reporting the current situation in a natural sequence.

It is very natural and neutral, especially in customer service or online shopping contexts.

Words like:

• 联系客服
• 退货
• 退款

are common in everyday modern Mandarin, especially for e-commerce.

So the sentence sounds normal in:

• chat messages
• customer support situations
• online marketplace conversations
• everyday spoken Mandarin

It is not overly formal, but it is also not slangy.

Yes, but the meaning shifts slightly.

• 想问 = wants to ask
• 想知道 = wants to know

So:

• 她已经联系客服了，想问怎么退货和退款。 = She has contacted customer service and wants to ask how to return the goods and get a refund.

• 她已经联系客服了，想知道怎么退货和退款。 = She has contacted customer service and wants to know how to return the goods and get a refund.

想问 focuses on asking the question.
想知道 focuses on getting the information.

In this context, both are natural, but 想问 fits especially well because she is contacting customer service.