The 'problem' is on both ends. You need more patience; you aren't dealing with McDonalds or Burger King. Remember too that they are often on the road locating things like a stack of Mafac brakes or a shed of jerseys. I've dealt with Renaissance Cycles many times over the past few years, making purchases directly from their store or via their eBay auctions (banana_brain and renaissance-cycles). When I send off a message to them, I mentally allow at least a week before worrying about it. This goes against my American psyche of instant gratification but eventually I always hear back, usually within a day or two, and I've always been satisfied with my purchases.
By the way, I just yesterday got a message that they've received my PayPal payment for two sets of Mafac Racer brakes plus other miscellaneous items and 'will let me know when it ships'.
Gary Chottiner
Northeast Ohio