It's a reasonable security feature. If you press your PIN
wrongly a few times, your card gets disabled.
Before you start bashing POSB for that, think about it: what if
a thief got hold of your card, and had unlimited tries for
inputting your PIN? Will you thank POSB for letting the thief have
a chance at withdrawing your money?
The same goes for many online websites. If you input your
password wrongly too many times, you may get locked out of your
account until you contact the site administrators.
In the end you only have yourself to blame for being too kan
cheong to even input your PIN properly.
What you can do now, instead of whining about it on sgforums, is
to actually call the DBS hotline to ask them for advice on what to
do. 