About 3 weeks ago i got an oil change, and just recently i checked my oil and it was empty. There was very little oil, and i know for a fact my car doesnt leak oil at all.So i took it to back to the place where they changed my oil, and they told me if im not leaking oil, then i must be burning the oil way too fast. What does this mean? Is something wrong with my engine? How can i figure out the cause of the problem?

If your piston rings are damaged, oil that lubricates the engine will get in your cylinders and will be combusted along with the gas and air. So while you are burning fuel, you are burning oil too. 3 weeks is pretty fast to burn all of your oil. If burning oil you will also notice your engine runs a little rough and you will have blue smoke coming out of your exhaust.

If you burned 3 or 4 quarts of oil in a week you would know about it. The car would be belching out white smoke all the time. They screwed up most likely and are trying to hide it.