Went to Mustang Ridge campground at Flaming Gorge UT from 07/09/17 to 07/11/17. Upon arriving noticed that the sites with the "R" designation could be reserved online. We attempted to reserve an open site by going to the webpage shown at the camp ground. We found out that reservation must be made 2 days in advance so we tried to talk to campground manager "Kenny". Kenny said we couldn't use the site because it must me done online. We explained the online booking issue and showed him that the site was open until 07/12/17. Kenny then said that he wasn't familiar with the website (posted at the campground) that we were using and we couldn't stay at the unreserved site. He did find us one next to the bathroom, the site smelled like sewage. Another guest offered the use of a site that she reserved because she wasn't going to use it. She contacted Kenny and cleared this with him. After we set up 2 tents and unloaded our gear, Kenny showed up and told us that we would have to move because we couldn't stay at a site with an "R" designation. We explained to him that the site was already paid for and walked him over to the lady that let us use it. He then became upset and said that this wasn't allowed because it was stealing. That's when I became upset and the conversation became heated. I explained that I did not appreciate being called a thief and I didn't like the way he was hounding us. Kenny even threatened to call his manager, which I welcomed because Kenny was being intentionally obtuse and not listing to reason. Once he saw that we would not back down, he backed off and even took back his statement about us stealing. I would also like to note that the male restrooms had poop all over both toilets for the entire stay. Maybe Kenny should worry about the upkeep and not hassle guests so much.