Maybe I'm old-fashioned... but why would you send 1/2 dozen emails instead of simply picking up the phone and calling him straight away? It's quite possible your explanation of the issue got lost in translation with email - something that could have been avoided with a live conversation with Dave. If I had an issue as serious as that, I'd be getting the guy on the phone pronto instead of relying on my email getting through to him.
Sorry to hear of your woes - hope you get satisfaction.
'11 Gas Gas EC250 | '06 KTM 950 Adv | '79 Laverda 1200