Fidelity Secure Drive service or accounts department is useless

I am very annoyed and angry at the service I received or currently receiving from Fidelity Secure Drive or Fidelity Services Group I sold my car in May and sent them a cancelation form as well as proof of payment for the cancelation and yet they still debit my account, I have unpaid debit orders, I have contacted them more than once and my issue is still not resolved