Why can't I unlock my ignition and start my car?

if lost keys would have been cheaper and easier to have cut at a dealer or automotive locksmith using vin --you said you gave keys and used key did you change cylinder if you did possible installed wrong if didnt then ignition switch failure ---theirs a tab/pin that goes into a slot that locks steering wheel in place

Trying smacking the shifter hard to the park position which it is already. There is a lock that stops the ignition from unlocking if the gear selector not getting into the P position all the way.

The steering wheel was turned when the key was removed. So when you try to turn on the key, turn the wheel one way and the other way to release the pressure on the key. The key should turn ok.
Hope this helps.

Either you got the wrong lock or you messed something up. Time to take it out and start over.

With the key in the ignition turn it to the "Accessories" setting. This will turn the lights etc...on.
With your foot on the brake slightly turn the wheel in the direction that it is already turned to. Turn the key to the "On" position with the steering wheel still slightly turned.
After the engine starts, the steering wheel should unlock. You may also need to put the car in gear before the wheel will unlock.

try turning the steering wheel a bit. it may be the steering has the steering lock in a bind.
if that dont work wiggle key sideways and in and out a little then have lock cyl replaced

You need to replace the key switch. It has a pawl in it that unlocks the lever that holds the steering wheel in lock position.

Make sure the gear selector is fully in park, alot of times if the cars wheel was turned when the vehicle is parked the steering wheel is locked in the turn position and it puts pressure on the ignition switch. Try turning the steering wheel slightly left/right and see if it kicks back. If it does you have tension on the ignition and need to hold it until the key is turned to the on position and it unlocks the ignition. If you can try to let the wheel come to a rest before turning off the ignition as opposed to holding the wheel turned and shutting off the ignition, this will avoid a locked wheel/column

All you need to do is turn your steering wheel to the left all the way till it stops then put your key in while still holding the steering wheel to the left, turn the key to the on position this should release your steering wheel!

Some cars will lock the steering wheel when the ignition is turned to the lock position. To try and start the car, grab the steering wheel and try to move the steering wheel back and forth while turning the ignition key at the same time. Be aware that the steering wheel could require a pretty good yank before the ignition unlocks.

Hope that helps