MTN deals not available to all existing customers

I went to the MTN shop in the Kolonade Shopping Centre (Montana, Pretoria), on 10 Jan 2024, to apply for one of their uncapped LTE deals as advertised. The sales assistant ran into trouble immediately. My current contract with MTN (decades old after numerous upgrades) is apparently on an ‘old’ system and I do not qualify for the uncapped LTE deal. Lots of customers complain about this issue according to the consultant. An interesting and nonsensical way to treat a 20+ year loyal customer!