If you are a victim of a crime you need to report it in person here: 
Questura - Via Migliore di Cino 10, Prato - Telephone 0574/5555 (24 hours a day)
Carabinieri - Via Pablo Picasso 30-32, Prato - Telephone 0574/7051 (24 hours a day)  

Call the dedicated Emergency Number 112 immediately and describe in as much detail as possible both where the robbery or mugging took place and what the perpetrator looked like. 

The more reports that are made, the higher the level of a security police presence in dangerous locations. Your reports help the forces of order to arrest criminals and thus guarantee the safety of all. 

Do not use self-defence unless absolutely necessary! In Italy, people must be protected by the law. 

Prevention is preferable...

When walking, make sure to stay on the pavement, using the one that goes in the opposite direction of oncoming traffic in order to avoid being mugged by someone travelling by bike or on a moped. 

Avoid narrow and unlit streets, especially at night time. 

Don't display jewellery or precious items. Choose a bag with a zip and keep it on the side of your body that faces the buildings, not the street. 

Don't display cash and don't keep large amounts of cash in your wallet or in your bag. 

Opening a bank account or post office account for your savings is advisable. (You can open a bank account even if you don't speak Italian, there are language mediators in most banks that can help you.). You will be given a bank card to carry out payments and to withdraw small sums of cash when needed. 

If you are the victim of an assault or a robbery...

Shout for help at the top of your voice saying "Aiuto, ladro". If the muggers/attackers have a knife or a gun, stay calm in order to stay safe.

Avoid talking to strangers who could use tricks to distract you and then rob you.