Disgusting service from CSI Rentals

I have never in my life experienced such rude service which I PAY for. I received a letter of demand saying that my flatmate and I were owing rent, which we had both paid in time. I called a rude Charlene trying to understand what was going on and she rudely attacked me saying that we hadn't paid for our water, which we had also paid for separately from the rent... She attacked me for something totally unrelated to what I was calling about. Id this is the way that CSI conducts business then I don't see how I can rest assured that my rental affairs are being taken care of. Such disrespect.. I'm disgusted to say to the least!