Vodacom not able to sort out issues

I would have given minus stars but you can not on this site. I have been trying now for months to sort out my contract at Vodacom about 4 times on the phone and was in stor today 07 march 2024 for the fourth tine this year with no sucsess. I upgraded my account in 2020 just befor lockdown. Then they started to charge me for 2 devices but I only got one. Finaly I got that sorted after a year and they refunded me. Now for the last year they are charging me for two extra contracts that I have never agreed or asked for and they cant tell me or give me proof that I took out these other contracts. and I pay my contract via eft. My original contract agreement was just under R1300 per month that gives me under R15600 for the past 12 moths that I had to pay and I have paid R22600 in the last 12 moths and they are telling me I still owe R6000. That does not make sense. I have no Idea how to resolve this because not even vodacom employees can or want to help me. Any advice on how I can sort this issue