It has occurred to me that we may be asking the wrong question.
I was talking to a utility company about a confusing charge that they sent to collections that I did not know about (she said it was billed separately...same envelope) and I continued to pay only the gas bill and not the connection fee so they took it off and send it to collections. The collections company said they sent only one letter over a year ago because the amount is so small ($22). They said they had called about once a month but kept geting a fax signal.