ok, first thing you need to check if those emails may go to your spam folder.

second - if you ever change your email address?

third - check if your notification changed - this happen to us before - didn't change anything but somewhat this has changed.

Go to seller hub - click on overview, then on shortcuts click on site preference, then click on communication on left hand side nav bar, then go to selling activity see if your item sold is in 'real time'.

fourth - could be glitch from eBay - thus just wait and see what happen in few days.