2012 fiesta key memory

[foshoow]

Hi guys. I have a 2012 fiesta I bought damaged. I fixed it and put new battery in it. Now when I put the key in in gives ignition but won't start or crank. Ford is telling me it's the chip inside the key fob but I don't understand how it can be the chip when it's the original key. Does that mean that every time I change the car battery I'll need to pay $150 to reprogram the key..

Any help appreciated