I've noticed that the notifications I send via my Telegram chat group seem to reach buyers most quickly. Not everyone checks their email regularly and searching through Facebook, Instagram or Band can be a chore.
Telegram is a messaging app but its completely independent of Facebook or any other app so if there were ever to be an issue with my Facebook or Instagram account & I couldn't post or message there, I can still text everyone in the Telegram chat group. Its very easy to customize notifications in Telegram so you never miss a post about new goodies!
If you'd like to join, please use this link & welcome to the club!