Sears GE Credit Coming after a Debit that was paid off 8 years ago Internet

I paid off my Sears debit that they had turned over to a credit agency over 8 years ago. Today I recieved a call from another credit agency telling me that Sears has yet again turned over this account to another collection agency. Now I am having to dig through boxes because we are military and have moved several times since we paid. To find proof that it was paid off. I would never recommend anyone getting a credit card through Sears. How can they try to recollect on a paid off debit I find this very harassing.