issue with MTN account

my reference number *** i opened an account with MTN in July last year with a new contract number and i kept paying with an old number.so when i got message that was in areas i told mtn that i have been paying and they asked me to go to FNB to go and get a proof of payment last year in october. and nothing has been done to pay that amount into my MTN account. each month my line is always suspected and its really inconviniencing me as i am busy studying and family matters as i cant get things done. now they have sent me to legal wise yet MTN is the one with my money.