A 2007 Roadtrek built on which Sprinter? T1N (2006) or NCV3 (2007)?
If the former, it sounds like it might be a well-known problem for which there are DIY repair threads on Sprinter Forum. Our 2006 is in the process of succumbing to this - sometimes the latch works, sometimes not. If we have to pull the door apart to fix the underlying issue, we will couple that job with the addition of sound deadening materials given that we had a good outcome doing that to the cab doors (description here