How do i remove 2 old bank cards from my account

I hope have posted in the correct section, as I am about to give up . I have been trying for two hours,to remove two old and redundant bank cards from my account as there will be attempts to charge them when the program sections that they were purchased with come up for renewal.
I have read through vast numbers of answers to Avasts FAQ’S, but none answered my problem.Can anyone help me sort out this problem please?