Camping World Service department does not know how to run a repair business. Vacaville, California

I took my motorhome to Camping World in Vacaville, California for some warranty work. After Camping World surveyed my problems, they, in turn, called my extended warranty facility to get authorization for the things that were in question. After having my RV for over two weeks, I decided to call them and find out what is going on with fixing my RV. The lady that I talked to explained all the things that were covered and not covered by my warranty. There were 3 things that had to be fixed and they were as follows: Change fuel line from gas tank to generator (not covered),replace PC board in refrigerator unit (under warranty), and replace toilet (covered). The fuel line problem was not covered but I was told that it was going to cost me labor and the cost of the fuel line ($545). The PC board for the reefer was covered under warranty including labor. The toilet was only covered for installation labor and a new toilet up to $110. I gave them the go ahead to install a new toilet and told them that I would pay the difference (new toilet was $179). So after making numerous calls to them to check status of the work, they finally told me on the phone when they could work me in to their schedule. When I went to pick up the RV a month later, the lady service advisor handed me a bill for a whopping $1383.28. After informing her that I was prepared to pay somewhere around $600 for what was my responsibility she told me that I had to pay for diagnostic fees (crock). They never informed me of these charges either by phone or when I asked what is this going to cost me. So after much voice raising I ended up with a bill for $873.36.