Need Advice: member not sending my parts

I drive a truck so I have to be careful when I bid on E-Bay. A lot of auctions end when I'm on the road and I don't want to get named as a dead-beat. If it's something I really want, I send the seller a question and explain when I will be back in town. If they don't answer me, I don't bid. But that is a pain when you really need the parts. I have found that most sellers are receptive to my up-front honesty and work with me.
But taking someone’s money and then basically blowing them off sucks. I guess dead beat bidders are a huge problem, but IF you take the money, that IS A CONTRACT and you can not only get your reputation hurt but it is also criminal.