I doubt the engine would even start at that low of compression.
Three possibilities: they never even ran it and pulled it off the shelf, truck, dirt lot, or what have you and shipped it out. Or they did run it and it was hard to start, ran rough, needed either to fire off, blew smoke, etc and they sold it to you anyways. Last, you did something wrong with the test, maybe a weak battery and turning over too slowly, compression tester not fitting properly and leaking, not turning it over long enough, etc.
With compression numbers that low, it's hard to see how they can't take it back on their dime if you're positive in your results. Even cold I would expect higher if the engine was "recently" ran