Get back to casa to log a complaint. Job done to your car is written on PMS receipt and problem occured only after their last-touch job, definitely it warrants for workmanship backjob. It could be just a loose parts, have them double check asap.

Check oil level for overfilled, underfilled, or no oil. Oil indicator should light in the dash and dissapear when engine running. If it doesn't, do not operate the engine and report to casa for possible oil sender or pump failure.