and we did a copression test by taking out the spark plugs and putting oil in the holes but theres no compression

Why would you put oil in the spark plug holes? That is NOT the way to do a compression test. Now if you did a proper compression test and there is no compression, them yes, it could be a timing chain, or if you only tested one cylinder, and no compression, the yes it could be a valve(s) The engine in your car is designed to run on a specific ratio of air to fuel (14 to 1). If this ratio increases by withholding fuel it can cause the engine to back fire through the intake system. The number one reason for this condition is a plugged fuel filter. A fuel-injected engine may backfire back up through the intake if an intake leak is present (causing the engine to run lean), or a fuel injection component such as an air-flow sensor is defective, ignition timing, a drop in fuel pressure, also causing an extremely lean fuel/air ratio. Check your PCV and EGR systems. Best way to do that is get your OBD codes read at a parts store, do not buy anything, write the codes down and bring them back here, one of us will be happy to help you figure out what to do next

PLEASE tell me WHY did you "put oil in the holes"??