No service but bad service at Discover Bank!!!!!

So I have a Discovery Cheque account and paid cash into my account via Pick'nPay. Either Pick'nPay and/or Discovery made a mistake and credit my account twice. I immediately informed the Bank and P'nP. For months nothing happened until I started getting phone calls from Discovery Collections and every time while I could not talk to them. Every time I asked them to call me the at a specific time when I will be able to discuss the issue. They never call back as requested. Next thing I receive a letter of final demanding and I am being threatened with legal action but at no time was I given an account to pay the money into nor asked for permission to debit my account with R1,000. When I call the speak to the agent in question (Ashleagh Lyon), she is either on a break (at 10 in the morning!!!!!!) or cannot take my call. Her team leader is also never available. Emails to collections gets answered with a standard automated reply and nothing else. I would like to pay them but how do I do this?????

Poor service 100% Incompetence 100% Customer service nil