MdSC400

Hi guys im new to this forum so im trying to see if i can get some help. I got my timing belt and water pump changed on my sc400 so after that when the car was started in the morning and when kinda getting in to it the car started to hesitate. A week later i was driving the car and it starts to hesitate and miss real bad...i pulled over thinking that maybe it was about to run out of gas since i was on E..i pulled into the gas station, get some gas and drive maybe a half a mile and when i stopped at the light the car cut off and wouldnt start back up..i got the car towed back to the shop where i had to timing belt work done at...long story short this was a week ago and the car is still in the shop, they cant figure out what is wrong with it and they say its not the timing on the car they are saying its not gettng any fire...the car cranks but it just wont start