Contract

I'm experiencing a very difficult situation with vodacom, I had taken my phone for repairs in mmabatho and the employees signed up a consent on my behalf that I agree to get my phone fixed without having been called to accept the quotation for an amount of R7000. I only received a call stating that my cellphone has been repaired, which started overheating and opening at the back after the repair was done. I took it back to the store and they gave it back saying there's no overheating issues. I then called to request a settlement for my contract which I paid it up and my number was immediately converted to prepaid,however I keep getting calls that I have an outstanding amount to pay. I just don't understand how because I no longer have a contract with them. It's frustrating how vodacom doesn't keep their end of the bargain and harass us with calls daily that we owe them. I'm really not happy with the amount of money I had to pay to fix the screen and pay up the account and yet I still can't find peace from Vodacom. Frustrating