Damn!!!! Help
You brought them a running car and a reasonable expectation to have it returned to you in running condition.
The dyno session was their project to tune their work, and it seems to have exposed a procedural error and/or parts defect related to the work you engaged them to perform.
If talks break down, I *STRONGLY* recommend you hold off posting their name until you've either resolved it in small claims court, or given up any hope of reaching a resolution.

