Occasionally you may receive an Amazon message from a manufacturer or 'authorized reseller' demanding that you raise your prices to MAP, or remove their products all together, as they are 'the sole authorized reseller'. Sometimes, these demands will be accompanied by threatening language, talk of 'reporting your account' to Amazon, and etc. Todd and Chris typically advise for you to completely ignore these messages.
You have purchased these genuine items from an authorized supplier legally and fairly, and as such have a right to sell it. There are always exceptions, however, such as NFL products, which have been banned from online retail outside of the NFL official store, or Nutramax brand products, which cannot be sold online. The difference you will see here is that NO ONE is selling NFL products on Amazon.
MAP is slightly more complicated, however. Typically, if the listing is full of varying prices all below MAP, you can ignore these messages as well. HOWEVER, if you notice on the listing that every other seller (or nearly every other) is at MAP, then raising your price is the route to take. This creates a win win situation for everyone as every seller is happy and sells equal amounts of each product. This is actually an ideal scenario that Todd says to look for in training. The only problem is that you must sell at MAP with everyone else in order for it to work out well. Use your own judgement in these scenarios to see if you should raise your price to MAP or not.
If you are ignoring these messages, you have nothing to worry about. Amazon will do nothing to you, as you are following all guidelines and are selling legally obtained product. The only way you can be stopped from selling these products is if the harassing party discovers where you are getting your product from, at which point they can blacklist you from purchasing their product. This can be avoided as long as you simply ignore their messages.
If you have any specific questions, feel free to submit a support ticket!