kingaku ni kakawarazu, goseikyuu to seikyuuteisei ni tuite keitaidenwagaisya ni kiku.

Here are the main readings:

• 金額 → きんがく
• にかかわらず → にかかわらず
• 誤請求 → ごせいきゅう
• 請求訂正 → せいきゅうていせい
• について → について
• 携帯電話会社 → けいたいでんわがいしゃ
• 聞く → きく

A full reading would be:

きんがく に かかわらず、 ごせいきゅう と せいきゅうていせい に ついて けいたいでんわがいしゃ に きく。

金額にかかわらず means regardless of the amount or no matter what the amount is.

It implies that the action that follows is the same whether the amount is small or large. So the amount does not affect the decision to ask the phone company.

This is because 〜にかかわらず is a set grammar pattern.

Structure:

Noun + にかかわらず = regardless of N

So:

• 金額にかかわらず = regardless of the amount
• 年齢にかかわらず = regardless of age
• 天候にかかわらず = regardless of the weather

The に marks the thing that serves as the standard or condition being ignored.

Yes. It comes from 関わる, which has meanings related to be connected with, concern, or have to do with.

In 〜にかかわらず, the form かかわらず is an older negative form meaning something like without being concerned with or without regard to.

So literally, 金額にかかわらず is close to:

without regard to the amount

But in natural English, regardless of the amount is the best translation.

They are related, but they are not the same thing.

• 誤請求 = an incorrect bill / erroneous charge / billing error
• 請求訂正 = correction of a bill / billing correction

So:

• 誤請求 is the problem
• 請求訂正 is the fix or correction

That is why both can appear together: the sentence is about asking the phone company concerning both the billing mistake and the correction process.

と connects the two nouns and means and.

So:

誤請求と請求訂正 = billing errors and billing corrections

Using と suggests both items are being specifically mentioned.

If the sentence used や, it would sound more like things like billing errors and billing corrections, which is less exact.

Also, if it used の, that would create a different relationship. For example:

誤請求の訂正 = correction of an incorrect charge

That would not mean the same thing as listing two separate topics.

〜について means about, regarding, or concerning.

So:

誤請求と請求訂正について = about billing errors and billing corrections

It marks the topic of the inquiry.

A useful way to think about it is:

• 何について聞く？ = Ask about what?
• 誤請求と請求訂正について聞く = Ask about billing errors and billing corrections

This に marks the person or organization being asked.

With 聞く, you often get a pattern like:

• 人に聞く = ask a person
• 人に〜を聞く = ask a person something
• 人に〜について聞く = ask a person about something

So here:

• 携帯電話会社に = to the mobile phone company
• 聞く = ask

Together:

携帯電話会社に聞く = ask the mobile phone company

That is a very common question. 聞く can mean several related things:

• hear
• listen
• ask

When it means ask, it usually involves asking someone for information.

For example:

• 先生に聞く = ask the teacher
• 友達に道を聞く = ask a friend for directions
• 会社に詳細を聞く = ask the company for details

So in this sentence, 聞く means ask/inquire, not just hear.

A more formal business-style verb could be 問い合わせる, but 聞く is still completely understandable.

Japanese often leaves the subject unstated when it is clear from context.

So this sentence could mean different things depending on where it appears:

• I ask the mobile phone company...
• We ask the mobile phone company...
• Ask the mobile phone company...
• One should ask the mobile phone company...

Japanese relies heavily on context, so leaving out the subject is normal.

The dictionary form often appears in:

• notes
• instructions
• headlines
• policy statements
• checklist-style writing

So 聞く here can sound like a simple action item: ask the mobile phone company.

It is not necessarily casual conversation. It can feel compact and matter-of-fact.

In everyday speech, you might hear:

• 携帯電話会社に聞きます = I will ask the mobile phone company
• 携帯電話会社に聞いてください = Please ask the mobile phone company
• 携帯電話会社に聞いたほうがいいです = It would be better to ask the mobile phone company

Yes, but it sounds a bit compact and written, rather than like relaxed everyday conversation.

It feels like something you might see in:

• a memo
• a customer-support guideline
• a checklist
• a procedural note

That is because of things like:

• the dictionary-form verb 聞く
• the formal noun compounds 誤請求, 請求訂正, and 携帯電話会社
• the structured grammar 〜にかかわらず and 〜について

So it is natural, but it has a somewhat formal, businesslike tone.