Bad experience with Customer service

The service is terrible and ridiculous. I had a month to month contract and when we moved ive informed then, thereafter we had problems with the debit orders. Not once did they phone of notify me the debit orders wasnt collected. I even had to pay cash at the new branch. Since then they didnt collect. Now ive received a notification i own them but i havent paid for the service/ they didnt collect the premiums. How can they held me reliable for premiums which was suppose to be collected and according to them they dont have my banking details but they have collected since 2019.