Laridian Consulting Inc is a collection firm that goes by two names. They are in the business of buying up debt that is determined to have been uncollectible by the original lender of merchant. In some cases the debts are already written off.
Under the Fair Debt Collection Practices Act, you are entitled to ask for and receive evidence of the original debt; and you are entitled to ask to work with the original debtor.
This company has a reputation for being aggressive and has good success with getting judgments and has even caused some arrests.
My advise is to not deal with them at all without having an attorney.
Be careful when answering their calls, because any thing you say could be construed to be an acknowledgment of the debt. In many cases, if you act quickly enough, the statute of limitations may have run out on any of this debt. BUt if they get it to court and get a judgment, especially in default, then you have a hard battle.
You would default if you got summoned to court and did not show.
My advise is to hire an attorney to write your letter to them regarding the fair debt collection practices act, and do not talk to them over the phone. your attorney will guide you.
You can read the fair debt collection practices act at this link: http://www.ftc.gov/bcp/edu/pubs/consumer/credit/cre27.pdf
You can also use that FTC site to file a complaint against them.