i encounter this problem last year.. i sent a hundreds of smses to starhub prepaid user but the user received none.. the problem was solved by changing the phone of the prepaid user..
this problem occur again last week.. i sent tons of smses to starhub prepaid user but non can receive mine.. problem solved automatically after a couple of hours..
my sister also encounter this problem.. she couldnt sent to numbers which start with 8.. but problem solved when she call their technical support officers..
my conclusion, blame starhub..
