Plasma TV / sears maintenance contract

I purchased a plasma TV last year. Like a lot of people they convinced me to purchase an extended maintenance agreement to the tune of $500.00. I called to schedule the annual service as recommended. The representative was okay but when he went to schedule the visit the times are limited to Tuesday and Fridays only. Then the time frame is from 8:00am to 5:00pm. (all day) with no guarantees. So in short I paid $500.00 for a maintenance contract that is going to cost me an addition $200.00 in lost wages to be able to use.