Vodacom fiber

I signed a contract with Vodacom fiber for 24 months and 7 months later the Wi-Fi connection was terrible I tried to reach out to them but still the issue continued. I decided to stop paying because I was not getting the service they promised, and they also disconnected my internet. 4 Months later I got a call from MBD that my account was handed over to them without a notification from Vodacom and they told me to pay R3500 in order for my account to be transferred back to Vodacom and I can have the connection back. I made the payment in good faith, and I got a call from mbd that they got the payment, and account has been transferred back to Vodacom. I called Vodacom and they said they have cancelled my contract and that I need to pay a R8000 more for cancellation they initiated themselves without even notifying me. Please assist as I feel like I'm being ****med at this stage.