I was told by counter staff that easyrentals insurance is not valid and i had to buy over the counte

The insurance requirements are very strict. If you don't buy insurance there, the pre-authorized deposit will be very high.

The service was quite satisfactory

The price was very cheap, but the information from QEEQ was incorrect. It was not inside the airport but outside. We had to call them, and only then did they send a car to pick us up. The operating hours were also not as listed on QEEQ. I specifically confirmed with QEEQ if it was within the airport.

After refunding the deposit, they deducted 100 euros without notifying, and there was no response from customer service for over half a month.

The staff took advantage of our hurry and didn't informed us (at all) about the refuelling fee and also they have double charged us the insurance fee although this was already purchased through easyrentcars.com