Kèfú shuō, bāoguǒ jì dào nàr yǐhòu, sāntiān yǐhòu jiù kěyǐ tuìkuǎn.

Yes. 客服 is short for 客服人员, meaning customer service staff / customer support.

In everyday Chinese, people very often just say 客服 to mean:

• the customer service agent
• the support team
• customer service in general

So 客服说 means customer service said or the customer service representative said.

那儿 and 那里 both mean there.

The main difference is style:

• 那儿 is more colloquial in northern-style Mandarin and everyday speech
• 那里 is a bit more neutral and slightly more standard/formal

In this sentence, 那儿 sounds natural and conversational.

Also, 儿 in 那儿 is an example of érhuà (the -r ending often heard in northern Mandarin).

寄 means to send / to mail / to ship.

到 after a verb often shows the result or destination reached. So:

• 寄 = send / mail
• 寄到 = send so that it arrives at / ship to

In this sentence, 包裹寄到那儿以后 means after the package is sent and reaches there.

Using 寄到 makes the destination clear. If you only said 寄, it would focus more on the act of sending, not the package reaching that place.

Because the sentence has two time reference points.

1. 包裹寄到那儿以后
   = after the package arrives there

2. 三天以后
   = three days later

So the structure is:

• first, the package gets there
• after that point
• three days later
• then a refund is possible

The second 以后 is measured from the first event.

So the full timing is basically:

After the package arrives there, three days later you can get a refund.

Here it means three days after the package gets there.

The sentence sets up a timeline:

• 包裹寄到那儿以后 = once the package has arrived there
• 三天以后 = three days after that
• 就可以退款 = then a refund can be issued / requested

So 三天以后 does not mean three days from now. It means three days after the arrival event.

Here 就 means something like:

• then
• at that point
• as soon as that condition is met
• only then, depending on context

So 三天以后就可以退款 means:

three days later, then a refund is allowed

It helps connect the condition and the result. It gives a sense of once that time has been reached, the refund becomes possible.

In many sentences, 就 marks an outcome that follows naturally from a condition or time point.

Because this sentence is talking about a policy or rule, not describing a completed event that already happened.

It is saying what is allowed after something happens:

• after the package arrives there
• three days later
• you can get a refund

Chinese often does not need 了 in this kind of conditional or procedural statement.

If you were talking about a specific package that has already arrived, you might hear something like:

• 包裹到了那儿以后...
• 包裹寄到那儿以后...

But in a general rule, leaving out 了 is very natural.

Yes, 退款 can be used as a verb.

It can mean:

• to refund money
• to get a refund
• to process a refund, depending on context

In this sentence, 可以退款 means a refund can be made or you can get a refund.

Chinese often uses the same word flexibly as either a noun or a verb depending on the sentence.

Related expressions:

• 申请退款 = apply for a refund
• 给你退款 = refund you
• 退款成功 = the refund was successful

Because Chinese usually puts time and conditions before the main action.

So the sentence follows a very typical Chinese pattern:

• 客服说
• [condition/time 1] 包裹寄到那儿以后
• [condition/time 2] 三天以后
• [main result] 就可以退款

Chinese often builds the background first and gives the main action last.

That is why this word order sounds natural: After the package gets there, three days later, then a refund is possible.

Yes, it could, but the nuance is a little different.

• 包裹到那儿以后 = after the package gets there
• 包裹寄到那儿以后 = after the package is shipped there and arrives there

Using 寄到 keeps the focus on the fact that this is a mailed/shipped package. It sounds especially natural in customer service or delivery situations.

Using 到那儿以后 would also be understandable, but 寄到那儿以后 is a bit more specific to shipping.

Yes, it is natural.

Chinese often repeats words like 以后 when each one belongs to a different time phrase:

• 包裹寄到那儿以后
• 三天以后

This repetition is not awkward in Chinese the way it might feel in English.

That said, speakers might also rephrase it in other natural ways, such as:

• 客服说，包裹寄到那儿以后，过三天就可以退款。
• 客服说，包裹到了那儿三天后就可以退款。

But your original sentence is perfectly understandable and natural.

Not necessarily.

可以退款 means it is possible / allowed to refund.

So it usually means:

• you are eligible for a refund
• the seller/platform can process the refund
• you may request the refund at that point

It does not by itself mean the refund is already done automatically.

If the speaker wanted to say it has already been refunded, they would use something more definite, such as:

• 已经退款了 = it has already been refunded
• 会给你退款 = they will refund you

A good way is to break it into chunks:

• 客服说 = customer service said
• 包裹寄到那儿以后 = after the package arrives there
• 三天以后 = three days later
• 就可以退款 = then a refund is possible

So the full logic is:

Customer service said that after the package arrives there, three days later you can get a refund.

This is a very typical Chinese sentence pattern: speaker + says + condition/time + result.