Hi,
We returned from Plakias and Elounda a few weeks ago. We hired a car (peugeot cabriolet) from the airport. We had to return the car with the same level of fuel in it as we picked up (between 1/4 and 1/2 full. We drove around a bit and kept topping up with 20 euros of fuel to keep it at that level. When returning to the airport (from Elounda) I stopped at a petrol station not too far from the airport on the main highway to add a top up of 10 euros. the owner at the pump took my 10 euros took the keys to open the filler cap . Allegedly put the fuel in (but the filler was at the rear of the car) gave me keys back and off I drove. The fuel gauge was slow to respond at the best of times but it didn't appear to move at all. I stopped at the next petrol station the last before the airport. I was ushered forward by the owner again keys handed over, fuel "put in", keys back and off I set again. The fuel gauge didn't move again. I was due to hand the car back shortly so went to the car rental depot at the airport where the rental company was fortunately more concerned about a faulty boot lock than the fuel reading. So I think I was scammed over fuel twice.
Moral of the story . If topping up before reu5rning your car to the airport check that the fuel you have purchased is actually going into your car