Contract Price Increase

In February 2015 I was contacted by BuyMondo offering a 1GB MMB deal to be added on to my Vodacom Talk Contract.for 24 months. The deal was for a 1GB DATA simcard only for R69.00 per month, unused data to be carried over to the following month. I was told by the agent that the amount of R69.00 per month would be applicable for 24 months, NO INCREASES! The agent who contacted me telephonically had obtained my account details, ID etc. from Vodacom and I was ALSO advised that ALL CALLS WERE RECORDED. I subsequently received the data simcard accompanied by a tax invoice from Vodacom, but no written Terms and Conditions as promised by the agent.Today I received an SMS from Vodacom advising me that from 1 May 2015 my subscription would be increased to R75.00 per month! I contacted Customer Care on 111 and spoke to an agent, I was cut off before any explanation, was put on to another agent but was cut off before any explanation. I then received an SMS apologising for the cut off, but that the prices were increasing anyway. I hope this problem will be resolved, to my knowledge a verbal contract is as good as a written one. Hopefully they can trace the recording of the call!