Twice In One Year

My number ported TWICE this year from mtn to cell c without my consent. Firstly, I cant understand why nothing is being done to prevent this. I say this because when you call the networks, they make it seem as if YOU have done something wrong. My reason for this complaint is because my issue was only resolved the last time after I complained. AGAIN, the porting was reversed and I am now back on mtn. I called the customer care to re-activate my BIS and AGAIN, I was told that they are unable to and will get back to me. Still no word! It is my BIS which I've paid for. Why should I have to fight and complain for what is owed to me and also, what is been done to stop my number from been wrongfully ported again. I've had this number for about 10 years so simply changing it is not as simple as you would expect, besides why should I just because the networks don't have proper systems in place to protect their customers?