Management Company Dispute

Tenancy Types and Management

I have been with the managemnt company for eight years and over this time have found them pretty unprofessional. Now however I have received complaints from my tenant about shoddy work and reluctance of Management company to do anything. I have had to now deal with work issues and am at present in dispute with the managment company over repeated shoddy work done by their contractors at high prices. I am hopefully going to sort the latter out myself but my question is - how easy is it to cancel your contract with a Managment Company? i have received a copy of the contract i signed and it doesn't include how to give notice. What it does show however is that it has breeched the agreement as I feel that they didn't ensure work was carried out at a satisfactory level although I presume they would disagree with this. Any help would be fantastic Thanks