Pathetic

I cancelled my contract last year November and was told that it would expire in December and that i had to pay x amoung. Which i did. I received proof of cancellation as well as statements showing that i do not owe any money. I then stopped my debit order but every month someone loaded it again. I went to the bank and stopped it several times and reversed the payments. Unfortunately i keep getting sms messafes and calls claiming im in arrears. The more i tell them im not and the more i send the proif via e mail to all different departments of mixtekematics, the more i am being harrased.. No one respond to any of my e mails and shen you try calling the number tgat called you it doesnt exist. I am gatvol of all the harrasment and i am at the point of seeking legal advice .This is absolutely pathetic