Ok - We all know that there will be some people you just can't please...I got my first a few weeks ago. They have been a customer for about a year - they put 0 effort into the lawn themselves - no water, their kid cuts it. Anyway - they had very bad dallasgrass and buttonweed this year - I made a service call 3 weeks after their regular summer app. They canceled a month later and do not want to pay for the summer app. - saying they already paid it and that they see no results from the program. They are slow payers and think their check for a spring app. was to cover the summer app. I have written 2 letters asking for final payment to no avail. They actually commented on seeing results earlier in the year - saying I was treating some of the neighbors lawn and they didn't't need to pay for their neighbors weed control. It's only $53 - but now principal is involved(I don't do contracts). What would you do?