Poor Customer Service

I have a contract with 8ta that I took 2 years ago. Recently I got an sms on the 18th of November alerting me that my bill has/will be higher than usual ,it continue to explain that this is because my contract deal reverted to the normal price. That was never explained to me when I took the contract. <br> The sms went further stating that I will be credited and an agent will be in contact with me to discuss an upgrade in order to avoid this to happen in future. <br> I called before the debit order was done , noticing that I will be billed double the usual. When I called an agent name Petronela assisted me , told me that she is logging a case number to the billing department regarding my query and said I will get a call from an agent with in 48hours. I never got a call then I followed up before the debit was done , they told me she never logged a case to the billing department , this agent told me that she has emailed Petronela to follow up on my case and I will get a call the following day, I never got a call. I even spoke to the manager and he said he will follow up on my case and I never heard from him, when I called again they told me he was busy. I was kept on holding +30minutes.