Bad customer service

I bought a book online towards the end of January 2018, payment was debited from my account mid February. Which was ok. During the month of March, same company I bought a book from debited my account. Which was now a problem as I've already paid them. I immediately called the FNB call center and spoke to a consultant to dispute the payment. I was advised to fill in a "cheque and debit card outstanding authorisation reversal form" & email it back to them. Which I did. The response was that it will be sorted in the next 5 business working days. Two weeks went by with no word from FNB & the payment hasn't reversed. I again called the call center & spoke to Nondumiso Nhlabathi who informed me that there was no trace/record that I had queried the matter until I gave her a reference number of the case. She asked me to forward her the form again while we on the call & she assured me she received it & that her superior has promised to look into the matter & will get back to me after the Easter holidays of which I understood. I'm still waiting. Yesterday I went to Protea Gardens branch to cancel my card as am worried the company may debit my account again. While i was there, the branch consultant decided we call them again & find out what's happening. Again, we were requested to forward the form & were kept on hold for over 30 minutes. I even left the bank without any response from the call center. This I regard as pathetic service from people who don't know how to treat their clients. I have been patient with you for about a month now & am getting sick of it.