How long should I wait before opening a dispute through Paypal/Ebay as a buyer?

[gypsycrew]

Hi there, 

Recently, I've purchased an item for a not inconsiderable amount of money. Upon my winning the auction, I paid immediately via Paypal. When I paid, I included a message with a request to let me know when the item was posted & to please supply the tracking number (as user said they were posting it registered mail).

I recieved an email the next morning saying that they would post it the following day. Two days after they replied to me they maked the item as posted, however did not add the tracking number in the details, or in a message to me as I'd requested.

I sent another polite request a few days later, in case it slipped their mind or such.

It's now been a week since that request, and I've receieved neither a tracking number or even a reply from the seller even confirming they got my message.

How long should I wait with no contact from the seller before considering opening a dispute? Normally I would continue to wait happily enough, but the item's worth quite a bit of money, and I want to know who I should be following up as I know there's a time limit on everything to raise the issue- the seller, if they've not actually sent the item, or the post office, if they've lost it in transit.

I figured I'd wait til mid next week to see if I get any response at all.

Thanks in advance for any suggestions/helpful comments :).