Thank you for using Just Answer.
I would need to see the letter to be sure, but it looks as if you are signed up to start benefits in December 2013, and that benefit is suppressed because it is before your full retirement age, and you have too much earnings in 2013. I have no idea how they could have year 2014 earnings.
If you can scan and upload the letter (with your name, address, and SSN redacted), I could give a more detailed answer.
Is there anything more I can do for you?