Unauthorized change of account

My cheque account has been changed to "pay as you use" by "unknown", I am being charged for every transaction I do and this has been going on for a while. Friday i chatted to 3 consultants on the FNB app (2 consultants dropped me when I requested clarification) , eventually the 3rd consultant suggested I log a ticket cause she cannot she who changed the account and why the account was changed and I also wanted refund. Ticket logged Friday - auto response said the query has been assigned to Service Resolution Centre, a consultant will contact me within 24-48 Business hours. Today is Thursday still waiting