my ex-boss says he is going to sue my for libel/slander.

My ex-boss got ahold of my resume and cover letter. In it I stated my wages were decreased drastically instead of closing the doors. I also stated that they could not offer me room for advancement in pay for years. He says he is going to sue me for libel since I refused to give him the list of employers I sent them to. The last six months he had to borrow 10,000.00 or more from the owner to pay the bills. He was past due on several bills, we even had a collection agency calling us to collect on a phone bill. The bad thing is I worked for a collection agency. We had to cut costs such as atty fees, entertainment of clients, etc... I believe all the signs were there to close the doors. Our base rate which determines commission went up 12,000.00 dollars. Do you think he has a case?

Based on the details of your post, it sounds like your statements were of a factual basis. If fact, they are not libelous.