clarov48, because this is your very first post on this board, I urge you to come back and provide more information:
From where is your phone service provided (country of mobile provider contract?)
Name of cell service provider?
Are you a resident of Italy or a short-term visitor?
What model and brand of phone are you using?
I recommend that others not answer this thread until the OP comes back.
In general, visible hyphens on a cell phone screen do not produce transmitted data. It is true that cell phones sometimes analyze a number and insert a prefix that is not visible on the screen.
clarov48, please see this page:
https://www.ricksteves.com/travel-tips/phones-tech/call-uk-europe