Cell C Refusing to do simswap after upgrade

My account was move recently from Glocell to Cell C as per agreement between the companies. My last invoice was received from Glocell with instruction to pay Cell C and they provide an account number to use. I made the payment but then received an sms from Cell C stating my account is in arrears. I picked up that the account number on the sms was different. I immediately phoned the customer care line and pointed this out. I were told to email the letter to the which I did. I received an auto reply but no further action. In the meantime I received a call asking if I want to upgrade, which I did and the new phone was promptly delivered the only catch is I needed to do a Sim swop. When I phoned the customer care line they refused to do it because "my account is in arrears". I explained the situation but "the system do not allow it". Asked to speak to a manager only to be told he is busy with another client and will phone me back. Apparently he was busy with that client for more than an hour but at least he phone back. The result was however no different. He only took my sim detail and reference number of the auto reply with a promise to escalate the matter. A day later and I am still waiting for someone to call me........ My problem is this: Cell C via Glocell cause the problem, they do not impower their call center staff to resolve the issue, not even the so called management and in the end the customer suffer...... My account is still flagged as in arrears with the threat to suspend my service plus they provided me with a phone that is currently useless to me. My last comment is the stalling tactics used on the call center line. You have to type your number to identify you, if you don't it do not allow your call to be answered however the first thing you are asked when your call is answered is what is your number? And then security questions. When you get passed to the next person the same process.... A perfect system to end complaint