MTN NUMBER HECKED

My MTN phone number was hecked, a simSwap was done without my consent. Luckily I called customer care and they were able to do a simSwap reversal I got my number back. But it is so unfortunate that the person is still using my number for WhatsApp with my pictures as thier DP. I went to MTN store in Pietermaritzburg to inform them about this query and all they could tell me was that they are not involved with any WhatsApp issues. Yet all this was done due to their negligent and they couldn't even try to trace the location of the person who did the simswap no help non so over. I am very disappointed since I have been using this number aince 2006 so it been almost 17 years and this is how I am being treated in the end.