Showmax and MTN

I only activate my Showmax month to month using airtime. My cellphone network is MTN. On 16 February I activated my account, deducted the money from my airtime and when I entered the voucher code it said its already been used. So I ask to resend it, again same message. I started a live chat on showmax site, the person told me they issued me with the same code as they did in January and someone will contact me. The next day someone contacted me, asked the problem and gifted me with 7 day free subscription so that they can work on it. Now I have cancelled the service that day and tried to reload - the message was I cant because I have an active subscription. Only I cant watch anything. So showmax says its MTN and MTN says its showmax. No one is contacting me and only getting we will prioritize your ticket. I dont want to buy a new voucher as I am afraid this will happen again, then Im just losing money and cant watch TV. So disappointed in such poor customer service.