If you are denied both reconsideration of the overpayment and a waiver (with or without a personal conference), Social Security can begin taking money from your check. They will not take your whole SSI check. The most they can take each month is 10% of your total monthly income. But if you show on your budget that you cannot meet your current ordinary and necessary living expenses, Social Security can take as little as $1 per month to repay the overpayment.
Because overpayment law is complicated and appeals can be confusing, it is best to talk with a lawyer as soon as you can.
If you live in Connecticut and have very low income, call the Statewide Legal Services hotline at 860-344-0380 (Central CT & Middletown) or 1-800-453-3320 (all other areas in Connecticut). If you live in another state, you can look for legal aid in your state here.