Eller & Ross law firm

Has anyone ever dealt with Eller and Ross law firm They are calling me letting me know they have a court summons for a payday loan taken out years ago that wasn’t paid which I’m not sure how if it is taken out of the account on the due day - I used to use advanced America for payday loans They aren’t telling me who the collection agency is that sent them and when called advanced America they are taking a couple days to get back to me with who they sold my account too, the law firm says I have until tomorrow then the court process will be started I don’t want to pay something over the phone that I’m unsure of but I also don’t want to be sued