No assistance for ongoing service after new contract

Went for new contract on a prepaid number to istore. At the time the store could not use the prepaid number but advised I must go in to an MTN store to migrate my existing number to the contract number. 2 MTN stores later I was referred to the call centre as the store said because it was done at an istore it could only me migrated via the online call centre. I was then advised by yhe online call centre it would be done but when calling back to ask a question a second consultant told me it could not be done and they do not know who can assist.