Have you been charged?
Ps it does say " Approximately 48-24 hours before the game you will receive an email with your exact seats. You must print your tickets or download them to your mobile before the game. " when you go to the purchase option.
It has a specific email address to contact if you don't have it.
Identifier of purchaser? I'm assuming my full name. If so... Nothing shows. However I feel like that's for official members only. I may be wrong though.
Did you check here? http://taquilla.fcbarcelona.cat/webapp/en/misentradas/