SIM ported with out permission ?

I have emailed your customer service department but no seems to come back to you with an answer to my query. I had a Mobile Number with CellC for many years, but somehow, MTN got a request from someone to port my number? Can someone please tell me who asked MTN to do that. Because it was ported on the 18/09/2019 and the same day my Bank Account was compromised for a considerable amount of money. I did contact CellC to complain to them. They say now I must contact MTN to ask you who gave you permission to port it. BECAUSE IT WASN'T ME, Why do we RICA a Number if Mobile Companies do as they what. I spent over two hours with my bank on 18/10/2019 until 1.00 am in the morning to try and resolve this query. I had to stop all my cards, and change my phone number with all my contacts and Financial Institutions. please contact me if you require the number which was ported.