2020 Jeep Gladiator Multi-point Inspection Missing Oil

Had my Jeep Gladiator serviced at Napleton Dodge Jeep Chrysler Ellwood City Pennsylvania and I had changed the oil myself less than a month earlier, yet after getting it back the day before my oil was low enough it didn't touch the dip stick, idled hard, and Lance the service manger an his staff questioned my ability to service the oil. I've been changing fluids in vehicles since I was in high school 20+ years ago. My first vehicle was a Jeep Cherokee 4 cylinder that was bought used and always breaking, it was a great teaching aid.