Hoping to talk to someone at Google about an email ! When that ever happens hens will grow teeth and pigs will fly.
I can't see the relation between Gmail and Uber. Anyway have you tried to uninstal the app ?
When you attempt to login gmail what error message are you getting ?
When you created the account did you register an alternate email address or phone number to which you have access?
When you created the account, did you register a secret question which you remember?