Rewards co lie to customers!!!!

A lady phoned me to upgrade my contract with Vodacom. She **** to me and sold me a contract more expensive than what she said it would cost. She said is would be R 309.00 per month and my invoice is R 428.00. I did not take a device and asked if I would be able to get a device instore and yes said yes I would be able to. I went to the store and they said no I can't get a device and that that these telephonic upgrade sales people lie to customers. Now I want to cancel this upgrade and I am been given the run around!! Do not do a telephonic upgrade rather go instore!!