In March 1992, a man living near Boston, Mass. received a bill for
his as-yet-unused credit card stating that he owed $0.00. He ignored
it and threw it away. In April, he received another and threw that
one away too. The following month the credit card company sent him a
very nasty note stating they were going to cancel his card if he
didn't send them $0.00 by return post. He called and talked to them.
They said it was a computer error and told him they'd take care of
it.
The following month he decided that it was about time that he tried
out the troublesome credit card figuring that if there were purchases
on his account it would put an end to his ridiculous predicament.
However, in the first store that he produced his credit card in
payment for his purchases he found that his card had been canceled.
He called the credit card company who apologized for the computer
error once again and said that they would take care of it. The next
day he got a bill for $0.00 stating that payment was now overdue.
Assuming that having spoken to the credit card company only the
previous day the latest bill was yet another mistake he ignored it,
trusting that the company would be as good as their word and sort the
problem out. The next month he got a bill for $0.00 stating that he
had 10 days to pay his account or the company would have to take
steps to recover the debt.
Finally, giving in, he thought he would play the company at their own
game and mailed them a check for $0.00.  The computer duly processed
his account and returned a statement to the effect that he now owed
the credit card company nothing at all.
A week later, the man's bank called him asking him what he was doing
writing a check for $0.00.  After a lengthy explanation the bank
replied that the $0.00 check had caused their check processing
software to fail. The bank could not now process ANY checks from ANY
of their customers that day because the check for $0.00 was causing
the computer to crash.
The following month the man received a letter from the credit card
company claiming that his check had bounced and that he now owed them
$0.00 and unless he sent a check by return of post they would be
taking steps to recover the debt.