It is posible to hack iPhone?

Background noise is common in a car, especially if windows are open.

You found a phone number provided by a third party that you call to give your phone number, IMEI and SN so they can trace possible viruses? Will it also ask your AppleID and phone-lock password for "verification"? You were correct to pass on making that call.

If you mean software non-Apple people write that code and try to convince you it is required, there will always be such people. Ignore the people who benefit financially ONLY in such matters.

Besides, any anti-virus Apple feels is justified is already in iOS.

What anti-virus or "other things" are you talking about? There none that come stock on an iPhone.

Either there was a lot of background noise when you recorded it or your microphone is failing.

Not a virus looking for a way in, but scareware designed to scare people into buying useless software thinking this will protect them from malware and viruses.