Issue with Trade partner Mondo and MTN SA; terrible service

Rewardsco SA is the worst service provider ever! I wouldn't recommend anyone to use. When they want to secure a sale and get a customer/client they are quick to call a person. But when you as the customer or client now have a problem with the service provided they don't even bother to pickup the phone to call you as to try and remedy the situation, or as a customer that you are a customer with under a service provider they service too. I'm being billed amounts I never agreed on or was even informed or clearly advised about and all they say is that "we apologize for the inconvenience" and whatever else does not assist me or solve my situation. One of their agents contacted me and offered me a wifi/data contract upgrade for R169 pm, Which I would start paying on 25 May 2022. Instead on 25 May 2022, I was billed R334.32 and that changed to R532.67, within the same month. June again, I wasn't billed the R169 I agreed to. Now their agents tell me this, "The first bill would have been higher as it includes the pro-rata amount for the 1st month and full subscription for the following month. Please call MTN on 083135 if the monthly subscription is not R169pm". And all this extra or additional costs I was not advised or informed about. My initial 24 month contract with MTN is or was supposed to end on 15 July 2022. This company is that worst, honestly.