As many we were attracted to book a car hire via Rentalcars.com
for their interesting prices. That was a mistake! Booking the car was user friendly but when it came to making the payment problems started. Booking from Europe our bank initially blocked the payment as they thought it was a fraudulent transaction. After several tries our payment succeeded but the app still showed that booking was not confirmed and we didn't receive any confirmation by email within reasonable time after trying to make the booking. As we needed a car we made other arrangements locally. 3 days before the car - which believed was not booked - had to be picked up we received a mail with basic information. As we went in the rentalcars.com
app the next day to check and cancel the booking it was too late (cancellation has to be at least 48 hours before pick up) and the cancellation fee was the total amount (in line with their T&Cs). What looked as a good deal ended up to be a terrible one. I wrote the customer service and send them all the screen shots to proof the apparent bug in the system but they were very unhelpful and just referred to T&Cs. Be careful.