You mention "airport manager". I presume you mean an actual EI employee. The airport manager wouldn't be, and shouldn't be offering you anything. Who was this EI employee? EI do not oversell flights so in general they have no issues with denied boarding. Flights either fly or they don't.
I also don't understand what you mean by passengers being involuntarily de-boarded due to crew shortages. How many?
Did the flight operate at all?
It sounds like a bad experience all round but you're missing a lot of info if you're looking for any help.