Unable to cancel contract

Your service agents are *********** ****s! At the beginning of November visited the Fountains Mall store in Jeffreys Bay. They were not able to assys me but put a call through to the service centre to cancel my contract. The agent I spoke with REFUSED to cancel my contract, instead insisting that I downgrade to one costing R35/month. After what seemed like forever I eventually agreed because I couldn't argue any more. I am a SASSA pensioner, having lost my job, and cannot actually afford a phone contract. This morning I get an SMS telling me I am going to be billed R225? WHERE AM I SUPPOSED TO GET THIS MONEY? My pension is R2100/month from which I must pay rent, lights and water, and rates before anything else. I am left with R500 for food and anything else I need.