I had a Galaxy S .... it was proving unreliable, kept losing it's config in middle of day for no reason.
On the Samsung web site ..following their directions, for support - in "My Samsung" opened support ticket ... after several weeks no response, opened 2 nd ticket ... no response.
I called the help desk, to be told they don't monitor the My Samsung tickets at all. !
Phone sent for repair .... came back no change.
Upgraded to Gingerbread ... again no change.
Sent phone back again, and called support .......... and they said they would exchange it, just arrived in post .... a brand new Galaxy S II
Their web tickets & systems may not be great, but have to give a great report on Customer Service if you talk to someone.