How should I say as a receptionist?

[Mickeynee]

Dear teachers

I used to work in a hotel as a receptionist.
I did not know then and still are wondering how to say
"you owe us nothing" politely when the
non-Japanese guests check out.

So I kept saying something like;
"You have nothing to pay."
"There is no balance left on your bill."
"There is nothing to be paid."
And I knew none of above were polite enough
as a hotel receptionist.
What should I have said?

Thank you in advance.

[Ouisch]

The usual phrase in AmE to indicate that the bill is paid in full and nothing more is owed is simply "You're all set."