No sound through speaker

It's started to have zero sound out - I think I've tried everything - there are no system sounds, no audio in/out, no ringtone or any kind of noise whatsover... volume bar on the side goes up and down, but makes no difference, tried eveything I can think of in settings mute/unmute, cold restarts, change ambience, but it's just totally a silent brick - ok if I worked in a library, but I keep missing phone calls - the vibration works, but it's not very strong It did have an "episode" a couple of months ago where it was totally silent as well, but just started working "on it's own" after a couple of days. This time, it's been like this for over a week now... Any ideas before I start investigations as to how resilient a Jolla is against "high speed wall impacts" ? LL&P Martin