Hard getting help in Vodacom

I have contract with Vodacom with no luck coz am using my other number, so in December I changed my bank due to *****ulent activities on it . Since December been trying to contact Voda but am struggling coz I can’t authenticate coz can’t remember my contract number , I don’t have contract copy so can’t reference , I need to change my banking and also do payment arrangement for the month of Dec and Jan monthly premium . Am being told to go to store and I just need to helped that’s all. Can someone please help .