Legal Question in Business Law in California

Yes, I'm afraid you have to pay it back. Most companies would agree to a payment schedule in circumstances like these, but the law does not require them to.

I'm assuming that you worked for the agency, that they issued your paycheck, handled the deductions, figured the amount due you, and also the dates on which you were supposed to receive your pay.

The general rule on accidental overpayments is that the party making the overpayment is entitled to have the excess refunded to them UNLESS two conditions are met, in which case the person who was overpaid is not required by law or equity to make a refund:

(1) The person who received the excess payment had no good reason to suspect it was an overpayment at the time, as for example somoen whose weekly paycheck is usually $525 and suddently gets one for $5,250. That's obviously an error, and the person receiving the check would not pass test number one.

(2) The person who received the excess payment has materially changed his position in reliance on the belief that the money is his. If you put the check in your dresser drawer, you have not changed your position. If you used the check to pay the rent, and had no other funds to pay the rent, you have materially changed your position.

I can't tell whether you meet the tests or not. More likely than not, you'd pass test #2, since you probably don't have piles of cash and you had to use, and did use, the $361. Whether or not getting an extra $361 didn't seem a little too much at the time, that is up to you to answer, both to your conscience and to the agency.