FNB CONNECT USELESS SERVICE PROVIDER!!!!!

I used to have a cell phone contract at FNB Connect but when my contract expired I moved the contract over to Cell C. FNB Connect actually gets their sim cards from Cell C but they operate as separate service providers. When my contract expired with FNB Connect I moved over to Cell C but I exported my number to Cell C in order to keep my existing number. This is almost 4 years ago if I remember correct! So since Monday 17th of August my phone was suddenly just not working, I could not make or receive any calls or messages only to find out that FNB Connect and Cell C gave my number to another client who took out a contract with FNB Connect on Tuesday the 18th of August!!!! How can their system allow for a contract number that is in use to be given to another client?????????? The worst part is they tell me that unfortunately the mistake they made can not be rectified I simply just have to get a new number and even though its not my fault I have to pay for the new number!!!! Its a joke!!!!! The system is somehow able to give out a used contract number but its not able to reverse it?????????????? FNB CONNECT AND CELL C ARE BOTH USELESS SERVICE PROVIDERS!!!!!!!!!!!