Don’t jump on after repair in the workshop

Hello I brought my Sprinter into a workshop because he jumped badly. The workshop changed the light plugs better but it didn’t, then they disassembled the whole engine and now he starts up and goes out again after about a minute. The workshop is by the way already over a month and I can not use the car. Can I sue the workshop somehow or have the car repaired at the expense of the workshop where else ? many thanks