Account details do not correspond to actual user

After having a contract with Vodacom in excess of 10 years, I again tried to upgrade in 2018 as is customary every two years. With a shock I found out that I could not upgrade, as some admin issue occurred on Vodacom's side which left my cell phone number, ID number with someone else's name & surname. The payments are debited off my bank account, I receive the statements and I have the sim cards, but the name on the system is not mine. I have contacted the accounts department, customer service and even went so far as to visit a Vodacom branch, but still this issue is unresolved. No one is interested in assisting to clear this matter. I have two contracts with Vodacom, both have the same issue. I am seriously considering cancelling the contract and moving service providers if this is not resolved as a matter of urgency.