Please check your bank statements routinely. A reader sent me an example of an instance where the city took the same amount that was due - twice. Once the day before the bill was due and once on the due date. I usually use the link on the city's website and hand enter my debit card information every month. I have not had a problem with that method, but many people seem to have problems making sure that their payments are properly credited to their account. This may explain the many people wanting to pay in person and get a receipt "in hand."
Let me know if you have problems with any payment method and I will pass it on or share it here.