mtn sim swap

good day

my phone recently got lost and im trying to do a sim swap with MTN but they are telling me my number is not populating any details on the system. I have used this number for over 11 years and is linked to all my important things I can not afford to loose it. When I call mtn's contract division because the prepaid side cant see my info they said my number is under tfg one to one data deals but my contract with them got cancelled 2 years ago. so I then called tfg who then advised they will release my number which they now state they did. mtn still says they cant access my details on their system even though tfg cancelled my contract and released my number...please help