You would be surprised how many times the letters are in error. Sometimes, when you call the number on the notice, the agent will look into it and tell you many of those letters were sent in error and you should disregard it. You should call them for details but make sure you call the number from the notice. Those agents are very nice usually and quite knowledgeable. You are correct in that you cannot amend a return without knowing what you need to amend and why, bu there's no reason why you can't go ahead and file 2017, just be sure to enter your SS benefits correctly. The comparisons with prior year numbers are just for your benefit and should not interfere with the filing of your current year at all.
