Many people don't realise that the correct way of informing OCBC
is to go directly to OCBC centres, NOT through
conveniently throwing things in some boxes.
Obviously, the dept which receives your info/updates simply just
dump your paper into the bin.
There is some... office politics going on currently,
so bewarned, anyone doing the same thing as yourself is tikaming
'send like no send'. Sometimes back, most NOT all of these papers are
diligently passed to respect depts, but that's because the admin
were kind enough, not because it's their duty. How I know? Not
important. Once the kind/good people all gone, of course all other
papers other than cheques, or application of credit a/c, will have
to tikam heavily.
Besides, all I can say is there is currently some other projects
going on that relates to various depts processing details.
One obvious reason why I, and some others, left is because of
office politics. 
Don't be so stressed up, but imagine those doing in the backgrounds
fighting the office-political wars (wasting precious time, energy
and happiness)... they are even more stressed up than yourself. Any
organisation is roughly the same, we either have good people to run
and stablise the show, or we have wars running. There's little
sense in hoping competition to oust out the weak, because which
good people don't wanna do their jobs but got involved in office
politics... 
Just as a (resigned) old colleague commented when we met last
month, '...something big is going to happen...'.
Go quickly to any OCBC centre and properly do your updates, and
email a letter to the customer service stating the issue to cover
yourself. Don't be a sacrifice of others' error.