When screening the call they don't identify themselves but whatsoever so if they were a legit collection agency or something like that they would identify themselves so that tells me they're a scammers
Someone who has bought your debt from a previous credit card company and they are trying to get payment. Just pay the credit card company directly much easier and settle with them. These people the collector's do not like to settle and rarely do. If so then it's just usually a couple hundred dollars.