Disgusting service from FNB

I paid off my Credit cards in March and all I asked for was a letter stating that this amount was paid on such a day and the accounts are fully paid and closed. Believe you me up until now I haven't received any response. I called in, logged calls on their website and all I get is reference numbers and a promise that someone will call me back. It is now three months and I am still being ignored. FNB used to be best in service but now it is the worst!!!!