y didnt accept my last month payment bills.

after i pay, they send an email that they received my payment.
but few days after they send this

'We encountered a system error in our earlier email payment reminder.'

We would like to inform that your 14 November 2010 bill is due on 5 December 2010, kindly make your payment before the due date to avoid service interruption.


anyone have any info on this?
tq