Thank you for your question.
The debt collector is supposed to follow up the initial contact with a written verification of the amount owed and the name of the original creditor. Failing to do so is a violation of the Fair Debt Collection Practices Act (FDCPA). If your daughter disputes the debt in writing, the debt collector cannot contact her again unless it is to inform her that a lawsuit is pending.
Please let me know if you have any follow-up questions.
If a lawsuit is filed without the debt collector ever verifying the debt in writing, that is actionable under the FDCPA and your daughter can sue civilly for damages and attorneys fees. Once the lawsuit is filed, she can counterclaim with that and provide any other defenses she may have. The debt collector would still have to prove that she owes the debt in some way in order to collect on it in a lawsuit.
The debt collector is obligated to send a written verification of the debt to your daughter. Failing to do so doesn't mean they can't still collect the debt, but your daughter could countersue under the FDCPA.
Yes, your daughter can request that verification from the debt collector at any time.