Unable to renew Lte Date contract at Telkom

I have a current Telkom Lte data contract which is coming to the end of its term. I am satisfied with the service and would like to renew the contract (service providers call it "upgrade"). I have received email notification from Telkom that I can now renew my contract. I have tried to renew the contract in store, online and via the call centre. I have however not been successful as their systems only allow me to upgrade to a voice contract. Why would I change from a date contract that I have had for more that 6 years to a voice contract? Telkom agents seem to have no answer. This seems like a bad joke but unless they change systems soon my contract will terminate and I will have to go somewhere else. And they wonder why they are face with retrenchments.