OPW DSW Waters RIP Off Phoenix, Arizona

I have had Opremium Water for quite some time. I started with them in Mesa and then moved to Phoenix. When I first signed up I got unlimited water for $45 a month. Was told that if I kept my contract for a year the water cooler was mine. Once I moved I started having all kinds of problems. They never delivered my water. And told me that I was only allowed 4 bottles a month. I had to call every month for delivery. They then started charging my account a couple of times a month. And proceeded to tell me that I was behind in my payments..which were automatically taken from my account. When I finally called to cancel my service I was treated with rude customer service..was told they were going scheduled to pick up my stuff anyway. The very next month they charged my account again. I had to go to my bank and have them reverse the charges. Bank told me they have that problem ALL of the time with that company. Within a couple of weeks of having the charges reversed I was sent a letter stating that I owe them close to $500...and if I returned the equipment my amount owed would be $86. Explain to me how I owe them $500 if the equipment is mine?