No service at all.

I took out a contract with ADT Security and was contacted for the fitment of the radio in my house, I took leave from work and awaited the arrival of the technician, I then decided to call the center on Monday morning and asked to speak to the manager and got the phone put down on me instead. I then made another call and got told i will get called back on Tuesday morning I am still waiting for the phone call on Friday. I also decided to cancel the contract as I have not received any service and got a call instead saying the technician is on his way to install the radio, and when the conversation went on and I complained about all that had happened and said i canceled the service as I had not received any service I got told that then i must pay the outstanding amount of the contract. <br> My question is how can you pay for a service that you have not received and continue to not receive?