Quick to bill but not quick to close your account

I have asked them to close my account for the 4th time. They don't answer my emails or close my account. The first time they wouldn't close it because my account was in a credit. Two months later after 3 more requests and the account is still open and they still charging me costs. I will not pay any further costs after the 3rd of March 2020. And if they don't close my account TODAY, I will get my legal team to assist in this matter.