Bests & Worsts Reviews from Amazon

I bought the access code from Amazon thinking I could trust them to give me the correct product, as I am an avid Amazon fan. However, the code was invalid. After sitting on the phone with Pearson (who runs MyMathLab) for almost an hour, they finally told me they couldn't do anything for me because it was a made up code. Whether it really is made up or just an expired one, I really don't know. Amazon was nice enough to overnight me a replacement, only for me to be told it too was invalid. My professor warned us not to purchase them off the internet and I learned the hard way to listen to him. I hope this doesn't happen to anyone else!