For a service that asks for your credit card number right off the bat - they should really provide a support phone number. I trust you with my credit card information and all you give us is a general support email? I don't want to write you an email that gets responded to in a week when it comes to my money. People will be upset by this no matter what.
On another note, I see a lot of bad reviews on your company masked by fake good reviews on Yelp. Way to go, Uber.