Delta mechical Home depot Fresno California

Delta mechical is contracted by Home Depot to install their products and or repair a product which is defected , 3  years ago delta installed a hot water heater which I purchased at Home Depot   The install price was 462.00 for there time at my home. Was 1 hour delta mech ill has been out to my home on 3 different times for repair 1 st time 99.00 2time 99.00 and the 3rd time 198.00 it seems they charge what ever they want now after 3years the hot water heater was defected so Home Depot step up and covered the cost of a new hot water heater. N the  other hand good old delta mech cal  was called out they charged my other 462.00 o and they say this is the best price I think this company is a ripoff and they can screw people because they are contracted with homedepot  someone has to step up and put the brakes on this company I have forward this complaint the BBB consumers be ware