Multichoice Billing Disaster

I've added decoders to my account. This was a pro-rata calculation. Instead of invoicing only the added decoders for the pro-rata amount of days, they've invoiced me for my complete amount of units. I've phoned, I've mailed, I've phoned again, I've mailed again....still no response. I've been on the phone for such a long time, I actually ran out of my contract minutes on my mobile. I have reference numbers...mean nothing. DSTV … you suck. For a major corporate company, you are unable to respond to a customer query (your mistake), you are unable to contact me and I need to pick up the tab. Disgraceful. If I give this service to my customers, I would be out of business in a second.