The ways you can contact each Airline are different and are stated on their websites.
If you don't know the web address of your Airline, find it on the list of airlines operating at Bologna airport.
Other questions on the same topic
What is the maximum allowed weight for hold luggage?Contact your airline to find out about the allowances of weight and size.
Why can't I manage to check-in online?
Contact your Airline to find out about the online check-in.