"We sincerely apologize for your experience. After an investigation,
we could not determine why the First-Class Mail piece took 20 days to
arrive at its destination. That is not a normal occurrence. We do
not know why there was a delay. The normal service standard for
First-Class Mail from Pennsylvania to Washington would be
approximately 5 days. Again, we apologize that we are unable to
provide a reason for this delay."

But of course, they'll still charge full rate and surcharges ... !