Is there a limit to how long I wait before putting in an unpaid item claim

[Saltire]

Buyer bought it on 26th November, was being reasonalbe and left it 4 days before sending a reminder, but have had absoultely no contact from them, not even a sorry I won't have fund till xyz date.

Try lodging one via eBay it tells you if you are too early

OK thank you. I'm geting pretty fed up now, sold another 4 things and waiting for 3 of them to pay!