Rentalcars.com Customer Forced to Pay Twice After Booking Fails in Skopje

I could not pick up the vehicle I booked online through Rentalcars.com in Skopje. I had to rent a car from another company at the airport by making a second payment. There is no way to contact Rentalcars.com. No one answers the phone number provided on the booking confirmation document that was sent to me after I paid. It has been a terrible experience.