Look out! Be careful! If you signed severance paperwork that said they could take out your health insurance premiums and they did not take it out then they gave you the insurance premium money in your check. When you cashed that check you took constructive receipt of those health insurance premiums. Even though they may have screwed up they can come back and bill you for those health insurance premiums, especially if you have gone to the doctor or gotten meds. I wouldn't put it past Sears to do so. If they do bill you or want it back call your state labor board or labor commissioner. Watch out! Been there with another company.
Hope @Ojn2Y7q-1fyr does not mind me reposting this as a thread, it's good info more folks should see.