My question involves collection proceedings in the State of: Illinois

When i was probably 18-19 i went crazy with opening credit cards and never paying them. I accumulated at least 4 or 5 with 2 being major. I left them in the past, because honestly, ive never had the means to pay any of them. This past spring i received a summons by one of the collection agencies. Automatically wanting me to claim i owe the dedebt and pay them over $3000. I have no idea who the original creditor is. Im sure my credit cards have been passed from person to person. I cannot afford to pay anything oworkin 10-15 hrs a week. I have read on many sites that i can fight it by asking them to show proof of EVERYTHING since collections agencies most of the time do not have many original documents. is this true?