I want my money back.

Good Day FNB debited my credit card R8.50 seven times durin June 2018. Reason given was insufficient fund alert while there was an available balance in the card. I went to the bank numerouse times and they could not understand the reason for this. I logged a complain and they promised to credit my account. When this was not done I contacted the bank again and they told me the complaint was closed and no reason was recorded. Was told Sibongile and Valencia is dealing it and will contact me. This has not been done. I sent another complaint and no response. Also they have double debited my account and when I called them asking for my money back I was told I have to wait until they bank the money. FNB service has become bad especially since I changed my account from private clients to easy account.