baesongbiwa nurakdoen mulgeoneul gogaek senteo-e munuihaessseupnida.

와 means and and connects 배송비 and 누락된 물건.

Use:

• 와 after a noun ending in a vowel
• 과 after a noun ending in a consonant

Since 배송비 ends in the vowel sound ㅣ, 와 is correct:

• 배송비와 누락된 물건 = shipping fee and the missing item(s)

Because 배송비와 누락된 물건 is treated as one whole noun phrase, and the object particle goes at the end of that whole phrase.

So:

• 배송비와 누락된 물건을

This is like saying:

• [shipping fee and missing item(s)]
  • object marker

Korean often marks the whole combined phrase once instead of marking each noun separately.

누락된 means omitted, left out, or missing.

It comes from:

• 누락되다 = to be omitted / to be left out

Then -ㄴ/은 turns it into a noun modifier:

• 누락된 물건 = the item that was omitted / the missing item

In shopping or delivery contexts, this usually means an item that should have been included but was not.

Because the item did not do the omitting; the item was omitted.

• 누락되다 = to be omitted
• 누락하다 = to omit something

So:

• 누락된 물건 = an omitted/missing item
• 누락한 물건 would sound like the item that omitted something, which is not the intended meaning

With 문의하다, 에 commonly marks the place, organization, or destination you are directing the inquiry to.

So:

• 고객 센터에 문의했습니다 = I inquired with customer service / I contacted customer service with an inquiry

Here, 고객 센터 is the target of the inquiry, not the thing being asked about.

Because 고객 센터 is not the object of 문의하다 in this sentence.

The object is the topic being inquired about:

• 배송비와 누락된 물건을

The place or organization you ask is marked with 에:

• 고객 센터에

So the structure is roughly:

• [topic]을/를 [place/organization]에 문의하다

It is understandable, but many speakers would find this more natural:

• 배송비와 누락된 물건에 대해 고객 센터에 문의했습니다
• 배송비와 누락된 물건 관련해서 고객 센터에 문의했습니다

That is because 문의하다 often sounds especially natural when the thing being asked about is marked with:

• 에 대해 = about
• 에 관해 = regarding

So the original sentence is possible, but 에 대해 문의했습니다 may sound clearer and more idiomatic.

문의하다 is more formal and is commonly used in business, customer service, offices, websites, and official communication.

• 문의했습니다 = I inquired / I contacted them with a question
• 물어봤습니다 = I asked

In this context, 문의했습니다 is the better choice because talking to customer service is a formal situation.

문의했습니다 is:

• past tense
• formal polite style

Breakdown:

• 문의하다 = to inquire
• 문의했- = inquired
• -습니다 = formal polite ending

So it is the kind of form you see in:

• customer messages
• reports
• formal speech
• business writing

A less formal polite version would be:

• 문의했어요

Korean often leaves out the subject when it is obvious from context.

So even though English needs I, Korean can simply say:

• 배송비와 누락된 물건을 고객 센터에 문의했습니다

The subject is understood from the situation. If needed, you could add:

• 저는 배송비와 누락된 물건을 고객 센터에 문의했습니다

But leaving it out is very normal.

It can be either.

Korean nouns usually do not have to show singular vs. plural unless that distinction matters. So:

• 누락된 물건 can mean the missing item or the missing items

If you really want to emphasize plural, you could say:

• 누락된 물건들

But very often Korean leaves it unmarked.

Both are seen, but 고객센터 as one word is very common in real-world Korean, especially in business and online use.

So you may encounter both:

• 고객 센터
• 고객센터

They mean the same thing here. The unspaced form is especially common in everyday usage.

Yes. Korean word order is fairly flexible because particles show each word’s role.

For example, you could also say:

• 고객 센터에 배송비와 누락된 물건을 문의했습니다

That said, the verb normally stays at the end, and some versions sound more natural than others. A very natural phrasing would be:

• 고객 센터에 배송비와 누락된 물건에 대해 문의했습니다

So the order can move, but the particles are what keep the meaning clear.