hi, thanks for your reply ,i changed it yesterday morning.

Did you tick the box that says something like "apply to all current listings"? Can't remember the exact wording but the gist is there.

As a temporary fix, exempt those buyers who contact you - assuming they're not being blocked for having too many unpaid strikes.  To see who's been blocked, go to Account > Site Preferences > Buyer Requirements, then click on the bit at the bottom that says something like show blocked bidders.  It'll show the reason they've been blocked and should allow you to exempt them from any blocks in that section.