stupid parents

I have about 125 students. Yesterday I noticed that one of them turned in a worksheet packet that was completely blank. This packet had been three days worth of class work and homework, and the kid hadn't done a single problem. So I went through the stack of papers I had graded but not yet returned, and found two more things of his that were incomplete, and by incomplete I mean practically blank. The kid isn't doing jack. So I wrote an email to the parent yesterday, explaining the situation and asking her to talk to her son about this. I want to know what the problem is. Does he not understand the work or is he being lazy? So the kid tells the mom that he did the packet and turned it in, and he thinks he remembers getting two of the same thing and handing one of them in finished and the other one in blank. And the mother believes him. So she writes back asking me to look for the other packet. What am I, @D*%& stupid? I take the time out of my day to investigate this situation, look at the grade book to make sure there's no mistake, and write to the parent asking for help. And this is what I get back. So I wrote again saying I think the three of us need to meet and look at the work he has been turning in. JESUS CARTWHEELING CHRIST I hate this job sometimes.