Supersonic supercr#p

So cancelled my WiFi contract with Supersonic, / super****.... received confirmation they received it...a consultant calls to try and change my mind...no chance...They send me confirmation of termination for 31 March... 31st comes they switch me off...first thing in the morning... Cool...They were **** anyway...Can I please get my cancellation letter so that I can get a new service provider....no chance. They refuse...I believe its a std tactic they play.... Tell them if they don't send it, I will come collect at their offices...Comes Tuesday..no letter and I drive to their offices...no wonder I can't get a letter, the offices are empty...