mens choice - please do some general eBay research before you post advice here.

1. Pay mmediately is not a good option for most sellers - it really puts a lot of buyers off.

2. A seller can quote what ever time he/she wants for payment to be made, but you can not enforce it in any way as eBay allows 4 days minimum before a dispute can be opened.

3. All sellers should have blocks inplace - for bidders with strikes, not phone verified etc.

OP - if you have no response or payment withi 7 days open a NPB dispute, follow through and buyer will either pay ot not pay in which case you will get your fvf back and buyer will get a strike.