Can't get in contact with buyer, how long do I leave it?

[Visitor7]

I'd be giving him until tomorrow at the latest. He said the 27th, no later. And considering you've gone to extreme measures to get in contact with him, and he hasn't replied.

[Daydream Believer]

If he doesnt pay by tomorrow, start un unpaid item dispute with ebay. Acording to ebays terms they only have 4 days to pay for an item unless otherwise stated by the seller