Extremely bad service

I ordered a gas heating system on 24th April with a delivery date of 8th May. After numerous calls and different replies each time or just no reply I got the first phone call @ 13.46 which I was unable to answer. A further phone call @ 15.09 I was told they called me in the morning to arrange delivery. No call was received until 13.46. I advised I am not home now but will be home shortly and then they can deliver. I said I have been waiting for more than a month for delivery so they can wait for me to get home. The person put the phone down in my ear. I then phoned to speak to the manager and again the phone was cut off before even getting through to the manager. Unfortunely due to Builders Southgate it was the first and last time I will buy from Builders.