Help with o2 xda graphite plz?

[kuljit55]

hello, i just have brought a new unlocked o2 Graphite mobile running on WM5, however i am experiencing a wired problem. It seems to work fine on o2, Vodafone & T-Mobile. However as for orange, it works fine only with an classic orange payg sim (white colour one) but whenever i insert a new orange payg sim (blue or orange colour one) it gives me a message "no service" :(

Has anyone ever experienced such problem? or is it possible that the phone is not unlocked properly and needs unlocking again? please give me some suggestions.

thanks