The Hartford stopped monthly benefits for repayment due to an overpayment. Once monthly benefits end do I still have to repay remaining overpayment balance?

The Hartford notified us of an overpayment once we reported receiving retroactive Social Security Disability. We immediately repaid what they requested as overpayment and the LTD monthly benefit was reduced based on the amount of monthly social security disability benefit now being received. 16 months later The Hartford sent a letter stating an overpayment due to their error of the reduced LTD benefit they had calculated. We did not have the money to repay the amount they were requesting so they stopped the monthly LTD benefit to be applied to the overpayment. That benefit will end as of May 2024 but there will still be an amount owing ($14,722.00) of overpayment. Will we still have to repay this balance? What can the Hartford do to us if we can't afford to pay? This disability claim was employer paid and there was an Erisa Claus, however we did repay an initial overpayment. Employer corporate is in Minnesota I am employed in California.