Bad Service & Incorrect Billing

Received the worst service from Netstar and then the best part is they are billing me more than the rate they've promised me. I renewed my contract on the 9th of December 2021 but the unit was only installed on the 29th of January 2022 despite numerous calls to the fitment center. When it came to billing, the first installment was R267.46 and then R174.56, after they have promised me that they are giving me a discounted rate as I wanted to leave due to other service providers being cheaper. Why do you not keep to the rates you promise to your clients?