SSDI and LTD

 My Hartford LTD policy is post tax benefits (meaning i currently dont pay tax on Hartford LTD payouts as i paid premiums with post tax dollars).  I was approved for SSDi in August 2019 and SSDi will be sending a 3 year lump sum in excess of 100,000....which i have to pay straight to Hartford.  Is there some deduction or credit available to me or am i stuck with an unexpected 20k+ tax bill (which i cant pay).  I'm really stressed out as i have to elect whether or not to with hold by the end of the week from the SSD (and go forward).  I dont know if i should try and with hold  (and risk the wrath of Hartford) or somehow pay the IRS for a benefit i did not really receive.  Thanks so much for any help.