Vodacom or their representative enages in ********* behavior

I would like to know from Vodacom if they respect contracts that have been entered in to or do they think that they can just breach contracts as they please? I upgraded one of my contracts on the 29th March 2018 at a contract rate of R339.00 PM. Got a confirmation that contract has been accepted and phone will be delivered. On Monday 03 April get a call from a Zandile saying that all contracts for the end of March have been cancelled and reinstated at the new price of R 389.00. I told her that this was unacceptable but she insisted that that was the way it was going to be. Just put the phone down and RAM arrived to deliver the phone with an invoice date of 31 March 2048. Now what contract had been cancelled when it was concluded in March already? Phoned her again and sai that it was absolutely not acceptable and this contract was concluded in March at R339.00. She insisted that her manager will not budge on this and I asked to speak to the manager Thursday 05 April. She said will get manager to call me the same day - I am still waiting. I call her again on Friday 06 April and she says oh she was just about to call me and the manager decided to give the contract now at the old rate of R339.00. Super now I open and do all my transfer. On Tuesday 10 April I get SMS from Vodacom that upgrade has been completed. This Zandile now phones me again and says a system error cancelled the contract we must now return the phone and apply again for the upgrade at the new price and all sorts of stories about not getting benefits of the contract. Can Vodacom please stop this nonsense with all these stories and please give me my contract at the price I concluded the upgrade at I am done with all this nonsense and I will not be sending back this phone. Very disappointing having been a Vodacom customer for more than 20 years and having had more than 5 contracts of which I have cancelled two already and will be cancelling the rest as they become due. Cannot deal with a company that practices these sorts of ethics, or engages in ********* behavior.