Ok, you bought a macbook, iphone or any other product from the Apple corporation. All looks good until suddenly something breaks. You have a couple of options, go to a mac shop and claim that this is part of your waranty contract and that you would like to have it repaired.
Now comes the tricky part, it might be that you no longer have a a warranty or that you have to turn in your machine and you are not willing to. In those cases you still have a second option. You can look at which parts are broken and go to the iFixit website and order the parts. iFixit have a lot of mac spareparts on stock. Also they provide you with step by step instructions on how to change the parts that are broken.