Worst service ever.

Hi We phoned Teljoy about Non Freezer freezing up and door hanging. After two call outs by Defy we were told they will bill us if they found that fridge is working fine. Since 1 July we told them this is a Non freeze up fridge, so why does it freeze up so much we can't even get the freezer door close. Two months later we are still battling for them to resolve the issue. Had to replace rubbers, insert bolt to fix hanging door, but still battling with freezing up. Now they threaten us to bill us for non working fridge. REALLY. Brand new fridge giving all this issues. Are you not maybe selling people duds from furniture factories. This is breach of contract. How do I cancel the contract?