I have a 2015 Hyundai Elantra SE that is completely dead except the dash indicators. I just had it into our local dealership this past August 17th for an oil change and multipoint inspection. Supposedly the battery was tested and indicated it was ok. Won't even crank, just ticks when ignition turned to start. Worked fine after the oil change. I verified that I didn't leave any internal or external lighting on. I did find the positive battery terminal clamp was somewhat loose, so I tightened it. No changes. Any thoughts?