I want to register for MTN MoMo but my I'd number it's already registered and I don't know how

Hello,I am experiencing a problem about MTN Mobile money,it says my I'd number was registered but I just heard about it this year.I emailed them my details and they said I registered last year September with cellphone number that I don't even recognized but my our address are the same.so I asked them to delete that account for me so that I can register the new one myself,but they are no longer replying my email.hellopeter please help me