Be especially careful of emails from the supposed gov.gr that fish for the naive to declare their details in order to get a tax refund.
It seems that the economic and energy crisis that has hit the pockets of the Greeks is the new bait of fraudsters. There is a campaign aimed at domains ending in .gr, in which fake emails are sent pretending to be from gov.gr and informing you that you have a respectable amount as a tax refund.
And since you haven't confirmed your bank account you should go to the link it has and do it.
CAUTION!!! It is not an official email from gov.gr. Always pay attention to the details, as in this particular example the email sender is firstname.lastname@example.org
Do not give your information directly to anyone who asks for it. Always research what you are holding in your hands 2 and 3 times. Attention to detail.