CellC retention is a ****

I have been a good Cellc upfront payment contract holder for years. Cellc decided to change this contract without my consent, furthermore CellC has not given me benefits due to me, even though I have paid upfront. I tried to cancel this contract, I have been send from pillar to post. I have made more than 15 calls from 27th of July 2020 alone, sent numerous emails with no response. Few of reference numbers are: ***; ***; ***. Some of the call center agents are rude and just transfer calls without understanding the problem or they make me hold and then drop the call.