It just doesn’t add up

We took the motorhome into the shop the other day to get a few things done. One was the Slide topper (awning) that was coming apart. One was a new muffler, one of the two was rattling like it was coming apart inside. One was a seal in one of the levelers that has been leaking slowly. And the other was to replace one of my center wheel caps that they scratched the last time I took it into their shop. Well after 7 hours I went to check on their progress. They had done the slide topper and just started the muffler. Now they wanted to keep it over night and put us up in their parking lot. NOT! I told them I will be back to drive it off at closing. At closing time they only had the Topper and Muffler done, gave me an invoice for 4 hours labor, which was covered under warranty, and sent me on my way. HUM… 9 hours later and only 4 hours charged and they didn’t have enough time to complete the other tasks. Something doesn’t add up. And to top it off, being the skeptic that I am, the next day I checked their work. Slide topper…Looks good. Muffler…Wait a minute, it still rattles?? No wonder! They changed out the good one and left me with the bad one, replaced the wrong one. 9 hours to do 4 hours work and they still can’t get it right! Oh yeah, they wanted to charge me $20 labor to tell me that it was a seal leaking on the jack. I asked them to replace the seal when I brought it in because it was leaking. I said, since I told you the seal was leaking then you owed me $20 and since you’re trying to charge me $20 to tell me the seal is leaking then we are even. The payback is, they are going to have to pay for another muffler and eat the labor cost to replace it.