Just write a letter and tell BA what happened. You have had a bad experience I agree. I use FCO fairly regularly and generally it is OK; never great but ok. I always think of it as preparation for Africa which is not so far away. My Roman friends say that the trouble is that Italy has no culture of consumer rights and that is why service can be so poor. If you want to see how bad it can get, go to the Hertz counter at FCO it makes BA shine like a star in the firmament.