RV Newbie??

[Jimbo]

We rented an RV this past weekend. Had a good time up on the Delaware. We brought it back in better shape than when we go it. The guy took it off to top off the propane and check it out and comes back and tells us the septic wasn't empty when he checked and showed me a blob on the pavement. I'm sure no $hit was coming out when we dumped it. Then he tells me the monitor says 1/3 full and there could have been some clogged which is why he said he told me to drive home with the valve open so it would work itself out on the drive home. I remember he said drive home with the gray water open after dumping it, so I said driving along with raw sewage dripping out didn't seem too legal to me so I closed it after it stopped coming out. He charged us $200.00. I'm thinking this is like the gas station guy who squirts anti-freeze under your car and charges you to fix a non-existent leak. Ahhh the lessons a newbie RV'er learns. Anyone had anything similar happen so I don't feel so duped?