Edgars *****lant purchases

I got a call from edgars that my account was in arrears, funny my account balance was zero cents. I went to the beach to check what happened and they gave me numbers for rcs to call and it was revealed there that there was a purchase of airtime on my account. Funny thing is I don't even have a card as there was previously a ***** in my account and I just want to have the account closed. Now they're demanding I pay the money, this is after they asked me to send affidavits that I did not buy, which I did but still I'm being harrased to pay for the money which I believe it was their own personnel that purchased airtime for themselves. They need to investigate who authorized that purchase and it will point to one of their personnel. I called, sent message on Twitter l, been to the branch, nothing seems to help.