MTN is no help

I’ve been trying to cancel a contract with MTN that expired years ago and I’m told to use 083135 that only has three options and no agent. They are still debiting me for a number I don’t even know or use. It’s so frustrating and with this economy I feel like I’m being de*****ed from my hard earned funds and I need it to stop. Does anyone know how I can get assistance this is now thousands and thousands of rands for nothing!!!