I would have driven into the dog tbh, plow into and stop vs driving into a ditch... leaving the road is the worst thing to do. a, because you could end up crossing the other side of the road into another car or b, strike a much bigger object such as a tree,power poll or in your case, a bank.
I've heard of other stories regarding parts/services, seems the best thing to do is go over the muppets (managers) head and threaten legal action if they are being dodgy.