The state rule, the city rule, and the one that follows your debtor

Sometimes - it depends on your contract and state law. Where your terms and conditions provide for collection costs and interest, and the applicable state permits it, those amounts may be added to the claim. That clause is worth having in your standard terms before you need it; ask your counsel to review it.

Potentially, but through agency law rather than the FDCPA. Federal telecom regulators have said a seller may be held vicariously liable under common-law agency principles for calls placed on its behalf, and 23 states extend their own collection statutes to original creditors as well as third-party agencies. The practical answer is to ask how an agency contacts debtors and to verify its licensing before placing accounts.

Statutes of limitation are state law and commonly run 3-6 years for commercial obligations, varying by whether the debt rests on a written contract, an open account or an oral agreement. In many states a partial payment or written acknowledgement can restart the clock - which is worth knowing before agreeing to a payment plan on a very old balance.

In some states, more than you would expect. Washington's statute bars an unlicensed agency from bringing or maintaining a collection action in that state's courts - so a licensing gap can make an otherwise collectable account unenforceable there. There is no nationwide rule making debts void, and this site does not claim one; check your state's page and verify licensing before placing.

It depends on the state - 31 jurisdictions require a licence or registration, Texas requires only a $10,000 bond filed with the Secretary of State, and the rest require neither. The rule that surprises creditors is that several states look at where the debtor is located, so a multi-state ledger can require an agency licensed in states you never thought about.