I just compared the calendar for Greece to Lunarium, it is correct.
You downloaded the wrong one, without daylight savings. Greece is in
north west, not south west. You are north of the equator.
The one you downloaded even states on the last page: "This file is for
South Africa, entries
do not observe Daylight Savings Time!"
From the correct calendar for people living in Greece, on the last page:
"UTC+2:00 DST (Bulgaria, Estonia, Finland, Greece, Latvia, Lithuania, Republic of Moldova, Romania, Ukraine)"
This is the one you should have downloaded:
UTC+2 DST (Eastern Europe)
Let this be a reminder to all,
check the last page to make sure it states your country, or at least a neighbouring country.