Doorbell only rings outside, no notification or chime sound

I have used my ring2 doorbell for several years now, never really had big issues. But from this year it has starting to have some serieus issues... several postal companies already complained against my doorbell (and other whom have the ring). When they ring the doorbell they hear the sound but my chrime and my mobile (x2) isn't ringing. I have checked/replaced the batteries, resetted settings, resetted router (its within 1 meter range) .. But it seems that the Ring2 doorbell has a 'warmUp' phase... or a wakeup delay. When I press the doorbell after the postal company almost was leaving I could hear both the chime and my phone ringing... the postal company guy als complained that he cant ring twice in a short period if no-one is comming.... Any idea what to do with this ...searched a lot online, read a lot complains but no solution... so this is why i startedmy post in heere.