Slide Maintenance

Seems kind of foolish if you ask me. Slides have motors and tracks with teeth for lack of a better word. From what you describe it sounds like there may be a missing tooth or the gear in the slide motor is broken or slipping. Sounds like the dealer is taking you for a ride. If at all possible I would pick it up and take it somewhere else, if that's an option. I wouldn't pay them anything, they are the professionals. If this happens all the time then they should be pretty fast at diagnosing the issue and fixing it. Have you asked them for a break down or what they have done? Can you manually crank out the slide without any hiccups? Best of luck and Sorry about your situation.