I hear you, I haven't had the best experiences from CW's service department, although we got some good deals from store side. Slide issues plague newer RVs as well, sometimes more so as they appear they are not as sturdily built, more than likely due to weight constraints from pressure for engineers to reduce overall weight on newer rigs.
Info on type of slide-out mechanism, manufacturer, and what were the symptoms, lots of knowledgeable folk on this forum with similar rigs that have faced the same issues. These rigs are complicated and many RV service centers just don't have enough experienced staff, still charging for a couple of hours is uncalled for, although not surprising these days.