First of all if you start taking social security benefits before your full retirement age (which is 66 in your case) - your benefits are permanently reduced.
Second - as your income is above certain limit - most of social security benefits are taxable.
So - you might consider to pay back that amount - and you will be considered as never started your social security benefits.
Then - we need to understand WHY the SSA determined that you was overpaid...
You can get Social Security retirement benefits and work at the same time.
However, if you are younger than full retirement age and make more than the yearly earnings limit, the SSA will reduce your benefit.
Starting with the month you reach full retirement age,they will not reduce your benefits no matter how much you earn.
We use the following earnings limits to reduce your benefits: If you are under full retirement age for the entire year, we deduct $1 from your benefit payments for every $2 you earn above the annual limit.
For 2016 that limit is $15,720.