i just come back from oversea then i realize that i cannot use my old sim card . just 2months ago, it was still fine( registered already) . now i insert the sim, it only display " cannot register simcard" or sth like that.
what i can do now to get it back?

thanks for your sugestion.
just got a sms from maxis that suggest me to buy 400sms for 2rm only and legal from 1am-7pm. and sht, i bought it without knowing its only valid for maximum 18hours. if u buy at 1am, u have 18hours to go, but if u buy at 5pm, you only have 5hours to go to eat all 400sms. thats so tricky and suck. really feel disaponted about maxis.