FNB Connect: someone else using my number!!!!

The Review is for FNB Connect: When my cellphone is off, people have been complaining for months that someone else is answering the phone and I didn't pay attention to it until my brother called and when the person answered, the man confirmed that the number was his. The problem is my data and voice gets finishes faster than I use it but FNB Connect doesn't seem to care. I called them yesterday and asked for a lodged a formal complaint. I received a call back later, confirming that the technicuians have resolved the issue which I was obviously happy with until today I spoke to a college who tried calling very early this morning but again my number was answered by someone that is not me. Does this mean he has been using my data and voice calls. The feedback I received was that the problem has been resolved, nothing about my lost data and calls just a simple thank you and good bye, which I most likely would have accepted if the same thing happened again today. Why am I not being taken seriously? Is my data, airtime and monthly contribution not worth getting resolution? How much am I valued as a client? How much am I worth to FNB as a whole???? I would just like to be taken seriously regarding my data and airtime being used and someone else answering my number when my cellphone is off. What do I have to do not to feel cheated??? Will I be heard????