When was your experience? At least nowadays there's https://help.uber.com, support@uber.com and @Uber_Support. I've used the first regarding a promo that didn't work for my ride, and they refunded it fairly quickly.
It was last summer. In-app, there appeared no obvious way to contact them to get status on the payment problem. Changing cards did not work either, which lead me to the conclusion that the payment processing was at fault especially since the same card was working fine for Lyft.
I uninstalled the app shortly after and exclusively use Lyft now.
I uninstalled the app shortly after and exclusively use Lyft now.