Runway incursion episode/incident Situation: I’m at the uncontrolled small airport (one runway and one taxi way).  The runway in the direction I will be taking requires backtaxing. I’m ready to taxi, I check the radio and get ‘clear and loud’ back.  I pull up to hold short lines, check the downwind, base and final, announce that I’ll be starting backtaxing and pull up to the runway (i.e. facing the final). To my horror I discover that there is an aircraft that must have just turn final. I execute 180 and exit the runway. The other aircraft lands and I re-enter the runway, backtaxi and take off. After I land I find a message from the owner of the flight school/club that own the place I used. He says that the airport called him, saying that I taxied in the line of approaching aircraft, but I couldn’t be reached on the radio. In fact, I did not hear anything during the entire episode (either from the airport, or the approaching aircraft). During my flight (1.7 hr) I used the radio repeatedly without any problems.
I am, of course, hugely embarrassed about the whole episode/incident. I’m a new pilot (130 hours) and I love the place where I rent the planes. I haven’t yet heard from the owner of this school/club (other than the initial voicemail), but I wonder if you could help me to answer the following: (a). what likely legal consequences will I face and (b) even if I don’t face any legal  consequences, is it likely that I will be banned from renting this school/club planes in the future.
From your description, you did nothing wrong. But, there is a possibility that one of you was on the wrong frequency. It is hard to prove that unless the radio calls were recorded. There is iPad software for recording your radio transmissions.
The more important lesson to be learned is that a nontowered  field is supposed to be pilot-controlled. But, it is perfectly legal to fly in pilot-controlled airspace without talking on the radio. Even if neither of you made a radio call, you would be within the FAA regulations.
The mistake that was made was that neither of you maintained situational awareness. You should always visually clear the traffic pattern while taxiing to and holding short of the runway. This is especially true for final approach. In the case of a high-wing aircraft, you will have to angle the nose of your aircraft downwind toward final. Otherwise, your wing will block your view of final.
P.S. It might not be a bad idea to file a NASA report.