My mom's number is also ported over to MTN without her consent

I just called my mom she uses two phones and her other number which is a Vodacom number is now being used by someone else, My mom's number has been ported over to MTN without her knowledge. When I called her right now another women answered the phone and I thought I dialed the wrong number, the lady told me that she bought her contract sim card at MTN yesterday 15/04/2019 and she was given my mom's number and she has been receiving calls requesting for my mom, so that means MTN ported her number without her knowledge she was not even aware until I told her that someone is using her number, MTN should investigate this matter. PEOPLES NUMBERS ARE PORTED WITHOUT THEIR KNOWLEDGE OR CONSENT THIS IS *****. We need our numbers to be ported back to Vodacom asap please.