2004 Chrysler Pacifica not sure anymore

HI so I took my car to the shop to get fixed, first it started overheating, then it it had a weird smell, then I heard something pop and my car stopped. I have a 2004 chrysler pacifica, remind you it wasn't shaking or anything it just cut off. So we took it to get repaired. He told us it could be the timing belt, water pump or worst case scenario the engine. SO they replaced the timing belt and water pump, the car started up BUT when I drove it it was hard to kick off it wasn't accelerating, he told me it probably just need to catch up on the time give it a few days, the next day the search engine light came on, we drove it back up to the shop and he said maybe its something else but he didn't know. Then he said he drove it then it stopped again. My question is if you were to change a timing belt why would it be shaking and hard to accelerate? We told him that same day he gave it to us. On top of that he did not test drive it before giving it back to us! The car never shook or had a hard time accelerating even before it stopped, it just overheated, funny smell and cut off. Rode smooth.