Need more info. Was there a event that led to the cracked oil pan? Like you heard a noise , were you running the car hard , does the motor turn over and just won't catch, if the motor won't turn over try manually turning it over with a large breaker bar to insure it is not mechanically jammed or seized . My guess is that if it turned over before the mechanic pulled the motor, then he has missed a step when mating it back up to the trans.
Good luck
Mongoose57