That insurance carrier is asking for a copy of the proof of insurance verifying that we are eligible for health insurance I need to request a copy of the paperwork sent to me previously as I am unable to locate it now.
That is okay, ask your carrier for another certificate and they have to provide it.
You can also use statements, canceled checks, memos, etc. to prove you had health insurance. You may also have to sign a statement attesting to that fact and how long you were insured.
Keep in mind, if you are converting from a COBRA to HIPAA plan, premiums can be 200% so they are out of reach of most participants.