Mtn appears to not need prepaid clients

After 7 years as a loyal prepaid customer on Mtn, I have received a total lack of support from their online call centre via WhatsApp, as to my query as to why a service I received has just been terminated. Their reasoning is I'm a prepaid client and therefore I am no longer eligible for that service and terminated the call. This has happened twice.

I'm sure that prepaid clients are a large part of their business yet we are treated with total disdain and no interest what so ever. I requested Mtn's marketing contact details and the call was terminated. I emailed them via the Mtn App and still no reply.