Cell Communication regarding Data Contract renewal

Having been a Customer of Vodacom for many years I have always been impressed with the excellent service I have received in the past especially in person at their various outlets. I recently received a call from their call center (I presume?) and was informed that my Data Contract was up for renewal and that I qualified for a special deal R149.00 pm for a 20GB anytime data contract (excluding value added service) and the lady clarified that this was not a 10GB Daytime & 10GB Night Owl (which was what my previous contract terms were at R156 pm). I had +- 8GB still on this contract at the end of October which disappeared on the 1st November and low and behold I now have only a 10GB contract. I emailed Vodacom customer service to kindly check the call made to me and have as yet not had a response. I would therefore advise anyone to rather go into their outlets to renew contracts than to accept some kind of a con over the phone.