Ring 3 Plus Outside Microphone

I'm having trouble hearing callers. I can hear external sound for a second or two then the sound cuts out. Outgoing sound has been fine - callers can hear me no problem.I've reset the Ring Pro 3 as mentiond in other threads and this worked for a period - a few days max and has stopped working again. I've tried deleting and reinstalling the app on my iPhone, tried a different iPhone, switched off bluetooth etc and nothing is working bar resetting, which I don't want to keep doing.Appreciate any other suggestions :smiley: