I finished my 12 month lease and my landlord send me to collections because I failed to give notice?

I don't know if your state laws are different so check with Consumer Affairs.

When you have a lease and do not sign a new one your move out date is implied by the last date your lease states. If you did not move out on that date and stayed beyond that date you transferred to month to month occupancy and you are required to give a 30-day termination of occupancy notice.

If you were officially out of the residence by that date on the lease you didn't need to give notice.