Allowing purchases off a blocked card. Avis and FNB ****

I bank with FNB for years now. The allowed a purchase to of them to go off on a blocked card. I think FNB are running a **** together of allowing ********** purchases on customers cards. Please help me understand how a bank allows a purchase off a blocked card that's been blocked for 2 days now.

FNB is not protecting ny needs or helping me out on this issue.