Have my acc frozen too. 'Our systems have detected one or more alternate accounts that are not linked to your primary one'
Next day my pal told me that he have same situation. It was because we did some small transactions to each other and used same IP when we met in one place with one wifi router about year ago. After couple of days he was unfrozen, but I still waiting for support answer (5 days) - yesterday I've created new ticket in case if dude (Johnny Garcia) who do the job on solving previous is sick or something like this - but still no reply. Poloniex, if you read this, please unfreze my account. It's ok if two different ppl familiar with each other use your exchange.