Charlie Echols Auto & R V Service

We agreed with the service place that they would use Castroil in our $400,000 motorhome. Got the motorhome back to our storage building 1 mile down the road and decided to check the oil stick. It was solid black. My husband called Charlie Echols to see what could have happened and they said that was normal and they used Syntec in it. We called Castroil to see why their oil would turn black so fast and they told us it doesn’t. It normally takes 500 miles to see it darken. They were worried the dealership got some bad oil so they told us to have it removed and send them samples along with the type of Castroil used. Charlie Echols gave us lies after lies. They told us not to call them anymore. I explained to them that we needed to get that oil out of the engine. The manager told me not to call. Castroil 10 days later got a hold of them and was told by the manager the oil used was not Castroil but instead Citgo oil. We had already taken the oil out and saved samples. Citgo oil is not a known oil to us and we would never had agreed to let Charlie Echols use it but Citgo did run a sample analysis for me. It showed there was old oil left in the engine and not completely drained before the new oil was put in. I want my $762.65 refunded to me because my receipt says I paid for Castroil and that is not what I got. The owner of the company, William Nelson, wrote me a snotty letter and told me he wasn’t giving my money back plus he didn’t even have my engine type correct. Who knows the truth of what they actually put in the motorhome. He states in the letter that they did us Citgo oil but it is better than Castroil. Please help me get my money back as we did not get any service from them but had to take our motorhome to someone else that would remove their mistake. I have letters, bills and reports to prove my case. Schubert fountain hills, ArizonaU.S.A.