Bad customer service and robbing of monthly benefits

Bad service..... Had a contract for 2 years for a wifi router with 40gigs of date 20 day and 20 night.... Contract only suppose to end in November but they decided to reduce my data and only give me 10 gigs then has the nerve to tell me that it was only a promotion but I'm still paying for the same installment in actual fact paying more because installment increased for a lesser benefit... Called them and requested to speak to a manager they have lodged my dispute and said I will receive a call within 2 days and I'm still waiting I called on Monday 02 September 2019 and it's the 05 September already.... You are beyond pathetic