Very Disappointing

I have a 8ta contract since 2012, and not one good thing come from it. it was mistake on mistake on mistake, but the latest is i tried to cancel my currently 8ta contract that suppose to end 2014.In January 2015 i phoned to cancel, the lady emailed me a form, i filled in then fax and emailed the form. Just to get a call to ask my ID number which was on the form. few months later i see instalment still active. so i phoned again just to be told i must come in to the shop to fill in a cancellation form, which my fiance and i did. just to find out it is still not cancelled. I am really really really tired and fed up with 8ta. why cant the deliver anything? not one thing i have ever ask was done.