Cell C is the biggest **** ever, they should not be allowed to run a network

I ported my number to Cell C in January. A month after getting the SIM card, my sim just stopped working. I was told I must have taken the sim and put it in a different phone which is not true. Had to pay for a sim swap. In June, my phone just stopped receiving calls with the error “The number does not exist”. I phoned them to sort it out. It took a full week to resolve. Last week I had the same error, after numerous calls to them the issue was resolved on Wednesday. I could receive calls from all networks expect Vodacom. Today the error is back. When someone calls me, my number says “The number you have dialed does not exist”. I am on a contract and they want to charge me early cancellation fees even though the error is on their side. I lost out on a big business deal because I appear as a *****, 1 minute my number is going through, the next it does not exist. I really regret porting to Cell C