Refund Question

I purchased something on my credit card, let's say it cost £100.

My statement was produced on the 15th of the month, but I was refunded on the 17th.
So I have a paper bill which says £100 owed.

When I log in to internet banking, the credit card still says £100 debt. Will it be next month that I see it has been refunded and therefore won't owe anything? Or does it go in sooner? If the latter, how long?

Thanks