not sure about Silvia spcialists, but if you are getting no joy from any of the site sponsors, have you tried a generic Espresso servicing company?
Not sure where you stay, (oops just noticed its Indooroopilly), but I stay in the Redlands and and get my Giotto serviced by a small company in Capalaba. They seem to do a reasonable job, my only gripe being, they take a while. Mine was with them for 2 weeks recently, because it goes in the queue etc, and suspect coffee businesses might get priority over home machines. I resorted to buying a Syphon to use in the meantime.* ;) They charge an upfront deposit of $77, for the check, and then of course you pay time and materials on anything they need to do.
I have heard of a company on the Northside, I think you sometimes see their small vans going about, servicing cafes and things.
I will not name them here as they are not Sponsors, but PM me for more details if you wish.