How do I get my car unlocked?

It snowed yesterday and was cold. Today my dodge stratus will not unlock. We tried both sets of keys using the unlock button on the remotes, they won't work, we also tried inserting the key into the keyhole in the door to unlock it. It won't work. I think its frozen but everyone says it isn't. It was about 25 degrees last night. Everyone is telling me that couldn't be it so I don't know what to do. I looked up customer service on the dodge web site and their not open on Sundays.