Backwards ? Thats not right!
Sure they didnt install a pass side regulator on the drivers side?
Or maybe they didnt install it properly, plus it should have lasted longer thean it did.
Dont know that Ive heard of that parts outlet. Ive bought a couple off ebay with no problems so it could just be faulty parts. I would contact them and check if its under warranty or something.
Also wouldnt hurt to check your power window fuse.
When I installed mine I used lithium grease where the cables slide and on the little pulleys shaft to keep them well lubed. The cable can get damaged pretty quick of that pulley isnt turning.
Good Luck and Happy New Year!