Impossible to cancel policy at Discovery insurance

It's impossible for me to Cancel my Discovery insurance. Phoned 6 times with no success. Always get sent through to another department or I get told that they will send a email to the brokers to phone me back to cancel the policy and the nothing. It's so frustrating and makes me furious If I must use my money to phone Discovery and hold on for 15min at a time and everytime nothing happens. If I'm struggling for 4 days just to cancel the policy. How long will it take to register a claim. I can not weight to get rid of this insurance company for good..