Bought a 2nd hand PS4, it's banned from PS Network, am I screwed?

Tweeted AskPlaystation, no response yet (30 mins or so), can't access Live Chat with a new account - 'slight delay recognising new accounts, try back in 4-6 hours'

Goes without saying I won't be able to get in touch with the person who sold it to me (3rd party website).

So Sony have banned him, he's got my money to buy a new ps4, and I'm screwed.

Any suggestions?