Long story short rental24 is just a broker ( no car) and work with Rental car SIXT
Book a Fiat 500 in santorini on October 22 starting at 10 am.
Full payment has been done up front to rental 24.
We arrived late on October 22 at 7pm. When we arrived at the counter from SIXT, our contract has been canceled and our car booked to somebody else.
Don't try to call rental 24, their call center is always inaccessible!
SIXT said they don't want to talk to us to fix our problems. We lost all our money with Rental24