Avis needs better management

Booked and paid at Avis Car Rental to be told by the supervisor Alain at the Cape Town Airport branch that he doesn't have to help assist us just because we paying clients. This after we've been told they incapable of loading a secondary driver or canceling our booking in order to rebook the same vehicle due to the primary driver having their license ******. Not to mention, they don't have a call center nor do they have staff in branch capable of dealing with a customer enquiry. Avis car rental have by far the worst customer etiquette that I have ever come across. And I'm meant to be a preferred avis member. What ever that means