Poor service delivery

I have a prepaid number with mtn for more than 20 years . I last topped up with airtime in November 2022 . I have not made any calls since November due to having a work phone number , but I still recieved calls/sms and did all my personal banking . My number has been cancelled not available on the MTN network. I immediately tried countless times to retrieve my number from MTN in last three weeks, before they issue it to another customer. MTN customer service champions were unable to assist. If this number is allocated to someone else surely all my personal information will shared and this in contravention of the POPI act. I am very concerned that personal information of myself would be compromised. Is there any way I can get back my number ? I cannot have my personal info comprised like this or have anyone have access to my personal information or social networking.