Cell C unfair bullies

My contract term came to an end but I was happy to continue with the same contract terms. Imagine my surprise when, without informing me, they cut the data in half but charged the same amount of money. I stopped payment and explained the problem to 2 or 3 agents and also went to a cell c store to try and resolve the issue only to receive a call today saying that the matter had been handed over for collection. The person that called me was rude and a bully. Definitely not someone that I want to speak to ever again. I would like to be contacted by cell c, preferably by someone who can help resolve the problem. This is not how you keep your customers, Cell C. If you had treated me fairly to begin with, I probably would still have been your paying customer.