Room number charge on Saturday

And what will be the ruling regarding drinks in the paid minibar? At the beginning of the vacation, the hotel owner fills the small refrigerator in the room with drinks, while at the end of the vacation, depending on the drinks that are missing from the refrigerator, the customer is charged. Will it be permissible to consume a drink from the refrigerator on Shabbat? There is no registration of a room here because the drinks are already in the room. The question is whether there is commerce in this.

I don't think so. This is not a way to buy.

Regarding the registration problem. Does it matter if it's Jewish or Gentile? In many hotels, employees have the option to save this data without violating Shabbat, such as putting stickers, etc. Does it make a difference if I know that he's hot? He'll probably write it down with a pen, but is there another option? And in general, why is it my problem that he writes it down? He's doing it for himself so he doesn't forget that I owe him money, right?

Without the registration, he wouldn't have been known to you. Your explanation doesn't sound reasonable to me.
If he has the option without registering, that is a relevant argument. All that remains is the matter of the bargain, and that can be discussed. Not unequivocal.