Extremely long call answering delays

Been trying to cancel land line for last 3 months. Account arrives, I call 10210 and WAIT FOR AGES before hanging up. Times like 18 mins, 25 mins, etc. Tried emailing through website and NO RESPONSE to email. Today another account arrived so I called cancellations again. Waited 20 mins. No answer. Tried billing option and waited 15 mins BUT did get a human voice. Wonderful, but she couldn't help. Then she transferred me to cancellations where I WAITED again for an answer. I did get a girl at last, gave her the details and ... she asked me to HOLD and not hang up. She went off and I WAITED ANOTHER 30 MINS with NO COME BACK from her AT ALL. Finally, after being on the phone for 50 MINS I had to hang up because I just can't sit on the phone all day! The automated response says high call volumes etc. but this is beyond ridiculous. And it's impossible to get a direct email address or proper phone number to call. I am beyond frustrated and all the way to INCENSED.