Worst service ever and nobody to escalate to.

After being a client of Cell C for about 8 years I now will never use them again. After terrible service I waited till the end of my contract as I wanted to port my service away from them. This was a year ago. After 3months of never getting hold of the right people because everyone was working from home no escalation points and empty promises from staff staff saying this will be my last payment and being sent from pillar to post I finally managed to get my account cancelled. I paid what they said was final payment as you can't port before in August last year only to be told I still owed another payment in November. I paid that and ported the number to Telkom Mobile (what a pleasure). Only to be phoned by someone in June to say I owe Cell C money again. My number was ported to Telkom over a year ago. They are so rude too. They then said they will check what's it's for as it must be a mistake and will call me again if they need to. No further call to me but today I found out I have a blacklisting against my name with TransUnion for my Cell C account. Never have I had such bad service from a company before.