United Propane Have strong doubts that this company has been delivering the propane that they have been billing me. Millersville, Maryland

I have been a customer of United Propane, since 1983. I use propane for central heat, cooking and for domestic hot water. Several years ago I installed a wood burning appliance in my house in expectation of lower propane useage. 

Last year I burned approximately three cords of firewood but saw no reduction in our propane useage. I thought this was odd and attributed it to colder than normal temperatures. I then got busy and put my doubts on hold. 

Outside of winter, we only use propane for hot water and cooking. We have modern appliances, a modern house and should use very little propane.  Back in July 2011 we took a delivery of propane from United. We are on a delivery basis were they come fill the 500gal tank and leave a ticket in the door. They pick the date of delivery based on historical useage. That ticket has a ticket date of 7/12/11, projected delivery date of 8/6/11, and date on their invoice of 7/13/11. All sort of confusing but people get busy and these things get lost in the shuffle of life. This time though when I payed the bill on 8/3/11, I checked the gauge on the tank and it was reading 73%. I checked the tank on 11/3/11 amd it was at 62%. Then on 11/30/11 (if that is the delivery date on the convoluted ticket) took delivey of 265.8 gallons in a 500 gal. tank with a reading of 70%.  Do the math.       Tom, Baltimore-Maryland