I was wondering what kind of interest to charge for late payments and at what point to charge it. One of my commercial customers hasn't payed a bill they recieved over 40 days ago. I talked to the property manager two weeks ago and he said he approved the bill. They just seem to be taking their time cuting me a check. The last time I called him he said he would look into it and call me right back. It's been 4 days.