We're sorry this happened.
Following this steps as soon as possible :
Log in to Gnosis Pay
→ go to Card
→ select Settings
In case it got lost :
→ select Freeze. It can be unfrozen at any time.
In case it got stolen :
→ select Report / Terminate. This make it unusable forever.
Then:
Check recent transactions for anything suspicious
Select Add new card (your old one can’t be reused)