Bills and leaving

[#1]

I intend to close my account on the 20th, with a bill for the upcoming month due before this, on the 11th. Am I right in thinking that I will be charged for the whole month on the 11th but then refunded for the days not used. So I only pay 9 days into that billing period?

Thanks.

[#2]

Assuming that you are out of contract, that should be the case.