ssi overpayment

I have a friend who is on ssi and was working and reported their wages to ssi. They stopped working almost a year ago but now ssi says they have an overpayment of like 4000 dollars. they asked for a waiver and it been almost 6 months since then. What is the worst that can happen can they just ask for it back or will they go to jail. During this time my friend had savings in their account well over the allowable limit (FROM WORK WAGES AND SSI INCOME) saving up for a car so if social security finds out will they just have to pay back the money or will they be in trouble for fraud. THERE WAS NO INTENT TO DEFRAUD THE SYSTEM. The individual thought they could save money to buy a car, The money is now spent and below the limit so they are good now. PLEASE HELP!!!!! - Is this your question? Add additional information