Q: Credit card fraud via apple online store

Use the email form here >  Apple - Support - Mac App Store - Contact Support

And you haven't done so, change the Apple ID password associated wtih the account > Apple - Support - Apple ID

Apple ID: Tips for protecting the security of your account

wife's ccard details to make a 849€ purchase in an other country

Odd that could happen considering credit or debit card credentials must be associated with the same country where you reside.

The Complete Guide to Using the iTunes Store | iLounge Article

Billing policy is the same for both the Mac App and iTunes stores.