Gazzac,
I assume from the above that your vehicle is not starting?
Be prepared for your wallet to be to be stretched.
Do you have a credit card size code card for the vehicle? If yes then the emergency starting procedure can be used on a diesel engine.
The details on the code card can be used to order a replacement key from Fiat. Alternatively a good auto locksmith should be able to provide a cloned key, but if the existing key is not being recognised, will this work?
If you use the forum search facility, you should find several relevant threads. There are several fixes, but some remove the security given by the chipped key.