Stand over the guy's shoulder as he changes your wipers in the parking lot of Autozone. Next time, you'll be able to do it yourself!!! Or better yet, have him tell you how to do it yourself while he/she watches you, to make sure it's done correctly. Maybe they have a "twofer" sale going on, and putting a spare set in your trunk will insure that your will have to put the next set on by yourself, without the security of the parts store employee standing over your shoulder.
Was your dad successful in getting your money back? I agree . . . what are dad's for . . . especially when dealing with a situation like that!!! Although I remember a situation where my grandmother's husband, and my husband hid together behind the coke machine an auto parts store/machine shop when an employee made the BIG MISTAKE of trying to physically intimidate (body language only) me into backing off on an estimated written price on machining the head of my slant-six engine!!!! During the fallout, gramps commenting to my hubby how clear it was that I was definitely his wife's offspring!!!!! Needless to say, I exploded on this guy and was all over him like white on rice at his attempts to use body language to intimidate me, while the menfolk of the family hid behind a wall and coke machine!!!! And, I was only 20 at the time!!!!