PATHETIC SERVICE!!!

I would like to state I am horrified with the service I received from Supersonic. I had canceled my service in August 2022. After chatting to the retention agent (Vanessa-I think that's her name) which confirmed I will not be liable to pay to pay anything that month. Then i got confirmation the fees were going to be waivered after listening to the call recording. Then months later i get told they didnt get the router , yet it was picked up. Then after a year later i get a bill stating I owe that months fees which should of been waivered and didnt. I then get confirmation on the 30th of November via email confirming a credit note will be passed and the account will be closed. I also called them on the 20/11/2023 which they confirmed the same. Now on the 21/02/2024 I get a final demand letter from the lawyers requesting me to pay these funds. I am disappointed with supersonic. I will definitely not be recommending them to family and friends and going to put this all on social media. If i dont pay this final of demand then i get a summons and a judgement for a fault on supersonics side.