Vodacom dont know their own Account holders

Being contacted by vodacom upgrades for +- 3 years now to speak to Sonica. I have my contract which is now prepaid for more that 9 years. My number was not recycled or anything. I spoke once to a vodacom person to assist in identifying whom the owner of the account was and they read my name so why are they calling someone when im the sole owner of the number. Your account shows right but somewhere a database has the incorrect information and im being harassed for nothing.