If they can't message you it may not be an Etsy problem. IT sounds more like something in your device settings to block them.
If you are using a P
C (like me) check your computer settings to make sure you have not somehow blocked messages from Etsy. IF you are using the APP some people advise either updating or actually uninstalling the APP and then reinstalling.
If it is not your device you are using then you will need to contact Etsy--there is really nothing else much you can do from your end to fix it.
