A platform that takes no responsibility at all.
When I went to pick up my car at Advantage after paying through the platform, they demanded ridiculous additional charges just because I had an international driver’s license (including all sorts of excessive insurance fees). I had no other options at the time, so I reluctantly paid. Afterward, I emailed Carla to request mediation, hoping to get at least a partial refund. However, they showed no intention or willingness to help. Just use Rentalcars instead. With Rentalcars, there were no extra charges, and I even got a free upgrade.