Struggling to cancel TV licence for more than year

Iv'e been trying to CANCEL my TV licence for almost more than a year because I sold my TV set and do not own one. I was said that I need to send in an affidavit which I faxed 4 times already and emailed them the scanned document numerous times. NO REPLY or whatsoever. Just sms's of an account and each sms the amount is more and more.. Is this now your sort of way to make extra money? Playing with time? HORRIBLE.