I can't help with your problem, but on my last Easyjet flight (in the middle of one of the BA strikes so the plane was packed) they asked for volunteers to be bumped. They had had two medical emergencies on the way out and didn't have enough oxygen cylinders on board to carry a full complement of passengers. Apparently no oxygen could be located at Faro and they failed to find another flight which could detour to Faro en route from elsewhere in Europe. They had to ask several times - each time the compensation increased - but eventually they got enough volunteers and we made it home, albeit several hours late after the length of time they had spent trying to find alternatives.

I'm amazed that you weren't either given compensation at the time or given something in writing so you could pursue it without too much of a struggle later. Has it been resolved yet?