I had a similar experience having recently left a mobile phone on the flight from Manchester to Dublin. First Ryanair says I should contact Dublin airport. So I looked at Dublin airport website and was pleasantly surprised to see a matching mobile phone was handed in on the same day as my flight. So I reported my loss via the website. A week later no response. So I tried phoning and got an answer machine which took my details. Again no response after a week. I don't expect to see my mobile phone again but I at least expected some sort of response from the airport. Is that too much to expect. As for the rude people who say it's your own fault for losing it, I hope one day you or one of your dependants lose something very expensive. Karma!
I should also add that I bought a watch on the flight and discovered it was broke during the flight. The staff said they could not take it back and I would have to complain in writing to the supplier! So don't buy any goods on Ryanair flights.
I had a very similar experience in Dublin recently with Europcar. Offered us an upgrade at a bargain price for the whole hire period and then charged that rate per day on the contract. Like you say when you are tired after a long flight you don't expect to be lied to and have to read all the small print. I will not be so naive next time.