I can concur with their shitty support. I guess iOS 7 autoupdated my Vine app and somehow logged me out. I tried password resetting every email I could think of, I tried to connect via my social network. No dice. My account couldn't be found. I email their support team with my username asking them if they could provide me with my email, do a forgot password to the email. I even linked them to a few direct vines I had created and saved the URL to. Their response was unless I could provide them with the Vine ID number of my user account they could not locate my account.
Seems I emailed them back and forth six times and I kept getting this canned message from them. Needless to say, I've given up and deleted Vine from my phone.
"Unfortunately, we are unable to locate the Vine account in question. If you can still log in to your Vine account, go to your profile settings and select either "Invite via text" or "Invite via email." From there you will see your Vine account ID number. Can you reply to this message with the Vine ID number?
If you no longer have access to this account, but can see the account in Vine search, press the more icon (three dots) on the top right of the profile. After that, tap on "Share this profile" and from there you will see your Vine account ID number."