It's never a good idea to say something like "a pessary cleaning visit is level _______." Leveling should be done based on the severity and clinical picture, and documentation of that. My personal opinion is if your providers were in the past always billing level 4 for this, they were likely overcoding. At least some of the time.
MANY pessary cleaning visits are pretty straightforward. Prolapse without exacerbation. That would be 1 chronic stable problem, low (level 3). Data for ordering/reviewing UA is minimal or none (level 2). Risk for cleaning a pessary without any additional treatment (no OTC, no Rx, no consideration of surgery) would have to be minimal (level 2). This leads you to 99212. Now if this particular patient had another problem being addressed, or an independent historian, or additional tests, or other treatment options considered, it could easily be 99213 or 99214. You must level EACH visit based on the clinical situation of that patient's problem, data and risk at that particular visit.
If billing on time, 99214 requires at least 30 minutes. I don't think most providers spend 30 minutes on the E&M service for an uncomplicated pessary cleaning.
Don't forget the overarching criteria is medical necessity. Does a routine pessary cleaning NEED moderate decision making? It certainly possible, but not likely in my view.