Vodacom ********** deals

In May I received a phone call from Vodacom stating that they are migrating their old uChoose175 customers to uChoose390. I was told that I would get more airtime at a lower cost that I am currently paying. I asked the rep to confirm that I will only pay R390 and nothing more which he confirmed. Then end of July I received a statement stating that I now will paý R620. I contacted Vodacom support on 135 and the rep said he will investigate and get back to me before 13h00 on the 5th. It is now the 6th and he never got back to me. They are *****elent and I wish to cancel my contract I have had with them for over 20 years.