Skydive aircraft pilot reported after landing a pilot told them there was a NMAC between their two aircraft which the reporter was unaware of.

Narrative

During a descent to land after dropping a load of skydivers around 13;500 MSL; I made my initial descent west and then to the north; and proceeded to join the traffic pattern to land. I made a downwind; base; and final call on the CTAF stating my altitude. I was following a Cessna to land and had him in sight at all times; and on ADSB. I also had an aircraft on a straight in RNAV approach in sight as well; and on ADSB; which I deemed I had plenty of spacing between. While on final; the RNAV approach aircraft behind me curtly asked; 'what's happening right now on final at ZZZ?' The Cessna I was following asked if he was being overtaken by the jump aircraft and needed to go around. Before I could respond and let the Cessna know that we had adequate spacing and I would go around if necessary; the RNAV traffic told him he needed to go around; and the Cessna made a right hand turn to the east. While on short final; I exchanged radio calls with the straight-in RNAV traffic regarding the pattern. An unfamiliar male voice on the radio then said they wanted to have a discussion with me; and I told them I would be shutting down at the FBO if they'd like to talk. I assumed this was an occupant of the RNAV aircraft and welcomed them to clear up any confusion. After landing; taxiing to the FBO; and shutting down the aircraft; a Piper landed and taxied at a high rate of speed to the FBO. The gentleman presented himself as a DPE conducting a PPL check-ride; and accused me of descending over them and nearly missing their aircraft on the base leg by 20 feet. I never saw or heard this aircraft; nor did I see them on ADSB. He continued to yell and threaten me with his connections at the FSDO; that he would be reporting me and seeking to have my license revoked. He later contacted my company and made threats with an ultimatum that I must be fired; which my boss felt pressured to do and did so later this evening. While reflecting on this potential incident tonight; I am still unsure of how I could've been as close to a collision as he claims since I was in a typical skydive aircraft descent profile. I will be seeking council and training to make sure a potential incident like this never happens again.