MTN worst service

I am very frustrated with MTN, i made an upgrade for a router and they have used my mobile phone as the router number now i can't use my mobile phone as the number is barred for calls and internet, i have called them since morning but Retention Department is not answering my calls for cancelation and i also went to the store but was told there's nothing they can do because i upgraded online. I am losing a lot of business opportunities because i can't access my emails or make calls. My phone number is ***