Superior Home Heating Oil Co

I had to call them to repair my heater and the first technician informed me that my house has a negative pressure and that was the problem. The second technician that came informed me that the first technician repaired the heater with the wrong parts. I normally pay my bill within two days of receiving it and I called them and they told me to just wait and pay it because they were in the process of changing the company over. The next bill I received had a late fee added to it and I called them to discuss the issue and they told me to just pay the amount without the late fees. I cancelled my contract with them not long after that and they still made an unauthorized delivery. I then started receiving calls and letters saying I had a balance and they threatened to turn it over to a collection office. I sent a certified letter to the CEO of the company and informed him I would sue him if he turned me over to collections. I later called the company and informed them that I had sent that letter and that I would sue them if I received any more calls from a collection company. They never returned my calls and I just feel like they provide lousy service.