Unsatisfied Client - Breach of POPIA

I have taken out a cellphone contract with MTN and have had my contract for approximately 4 months now. From date of activation it was noted that my cellphone number was and is still currently being used by another person. I am unable to install or use WhatsApp as I am promoted by the phone that the number is already in use. Furthermore , I receive bank transaction notifications of the other user. This is private information, I am able to see amounts withdrawn and balance of accounts!

If this is the case. What information of mine is not open to that person.

I have logged this with MTN and the response as rather pathetic. They would rather loose me as a client than to resolve or infact their alternative is " just change your number"

I am paying for a number that I cannot use as my own. This is a breach of contract and POPIA.