The previous owners of my house left one of the 420lb tanks. I didn't want it. Amerigas started trying to get me to sign up for a monthly rental/fill program. I ignored them. They finally sent a letter that was trying to be intimidating that if I didn't immediately pay, they would repossess the tank. I ignored that as well. They never came - that was 8 years ago. I guess I own 300 lbs of propane now...
Also had an unnecessary, complex water filtration system in the house. Those guys were even more obnoxious, including sending letters saying my water would become dangerous, etc. I have our water regularly tested directly from the well and it has never been everything but perfect. Their system has been bypassed and is sitting in the crawlspace.