It won't open and the keys don't work

The answers to your problem are very numerous.
Usually what has happened is that when the lock was installed the pins (the part of the lock that rides on the cut part of the key) were not facing down. This allows dirt and debris to collect in the pin holes and also if a spring breaks it won't push the pin up to the cut part of the key. Some locks you can't even rotate to a position that faces down.
What I suggest is removing the knob or lever lock from the door and blowing out the key hole with compressed air. Work the key back and forth through the lock and blow it out again. If this doesn't work ... try and get a refund or a replacement from wherever you got it. Remember your time is worth money and so is your frustration. Don't waste allot of time trying to fix something that can be replaced relatively cheaply.