Like everyone else said, you more than likely just wasted $50. There couldn't have been that much sludge in there to flush out to get stuck in the pick-up. Did I read correctly that your car only has 16,000 miles on it? I'm sorry, this is a joke and I wouldn't trust these guys again. Seriously, changing the oil on a Subaru is the easiest thing I have ever did, besides maybe changing a fuse. The oil filter is the easiest to get to I've ever seen and I'm sure you know how to loosen and tighten a single bolt. Plus, you'll save money, know it's done right, and have a sense of satisfaction from doing it yourself.
-Charles-