Stay away from this company

I used to be a happy ADT client, then the merger...since then ~I have tried to get them to understand what a panic button means..to no avail. We press the panic button and we receive a phone call...I expect that when I press a panic button that a guard arrives at my house. Unfortunately the new company are unable to understand this as was proved by three tests in April....so I cancelled...by mail..and have the mails. Tyson of Fidelity does not understand this and persists in trying to debit my account....this after three telephone conversations confirming the cancellation.