Dollars and $ense

How come I got a bill for $0.18? It's from a long distance provider I no longer use and apparently I had a service charge that was pro-rated for the year coming out to less than a quarter. Now I know big companies cannot take right offs for every little bill but think about the math for a minute. The postage to send me the bill was more than the bill. The check I will write is going to be more than the bill and the stamp is more than double the bill. So, I might count out 18 pennies and put them in the envelope. Of course, some poor fool would have to process and count my change and I can't do that to anyone in good faith. I wonder if I don't pay if it would go to collections? It could accumulate decades of interest charges and I could lose my good credit rating.