For what it's worth, Deb... I found this:
"Midland Funding LLC is a legitimate debt collection agency that focuses on consumer debts under their parent company, Encore Capital Group — a major debt buyer. If Midland contacts you, you should first validate the alleged debt. Once you verify that the debt belongs to you, you can choose how to deal with Midland. Your main options are disputing the debt (if the information is incorrect or you disagree with the debt amount), or negotiating a settlement so you end up paying a portion of the debt."
(Have you checked your credit report? I know you don't have credit cards and stuff, but since this seems to be a real collection company, I think I'd want to at least know what's going on.)