Timing problems and a shaky mechanic

My 1992 Honda Prelude Si, 158,000 miles, leaked coolant the other day. I took it to a nearby mechanic I had never used before, hoping not to overheat the engine. He said my water pump needed replacement. I asked about the timing belt and he said he included that in my estimate ($650). It took him a week, and when I got the car back, the engine was hesitating to accelerate, was loud and vibrating. I brought it back to him and he admitted that he had trouble aligning the marks on the belt, and that he didn't own a dowel that now he thought may have been necessary to align the balance shaft. He also admitted that he didn't replace the oil seals, since there was no oil leaking. He is waiting for the dowel and will try to realign the shaft. I am so deeply suspicious of what is going on. I called the dealer who said that timing belts are very sensitive and require experience. I have looked around on this great website and haven't seen exactly this issue. Any help? Thanks so much!