false information and now its my problem

I made an online purchase and got an electronic call from STD Bank to make sure i approved these purchases. I said yes to all 3, they decided to decline 1 of them anyway and stop my card. i tried again, nothing happened. Found out card was stopped while trying to pay at PicknPay....i then called STD bank to which they apologized and re-instated the card. I asked about the 2 transactions, they said that both were declined and i must try again. I did. Now i am R1999 poorer (and 1 wireless modems richer) as the 2nd transaction did take place. they wont reverse the charges and say i must take it up with supplier. I asked for recorded conversation so i could show fault belonged to STD Bank, they refused to give it to me unless i knew exact time and date and person i spoke to- even though only call i made to them in last year...not hard to locate.