Legal Question in Business Law in California

Of course, unless the rights to collection have been sold or transferred to someone else or some other business.

Generally, a debt is not extinguished merely because the creditor business "closes." First, to close a business has several possible meanings, depending (in part) on whether the business is a sole proprietorship, partnership, corporation, LLC, etc., and in part on what the business really did when it closed. Today is Martin Luther King, Jr. Day, for example, and a lot of businesses are closed. They'll be open tomorrow, and trying to collect their debts. Ceasing to do business for a day, a month, a year, does not in itself affect the collectibility of a debt. Neither, generally, does changing the business name.

When an incorporated business "closes" by going through a process that involves formally dissolving (ceasing to exist by giving up its state-granted charter, for example), it must pass along any and all assets (after paying or providing for all its liabilities) to those parties entitled to receive them. Normally, this is the stockholders. If the stockholders of dissolved Corporation X also happen to be the stockholders of new Corporation Y, then they can cause Corporation Y to pursue the debtors of former Corporation X.

In sum, if you are the debtor, I'd ask how the new business acquired its rights to debts owed to the old business -- but be prepared to accept any reasonably plausible explanation.