In late 2013 I Believe that apple changes their keys to have "Better supported Keys" The only thing you could do is buy an after market keys therefore is keys fall off you can replace them with the stronger and probably cheaper than apple charging you $50 to put a couple of keys on... There is also the option of buying the keys all separately if you don't want a set of extra keyboard keys laying around. I'll Drop a link down at the bottom of this response for a website to buy the keys you need. On the website they even have an install guide and purchase guide.
Best of Luck Erica!
Galen Nekvasil