If it is an original creditor, they may send you details of the outstanding debt amount and it will be considered a debt validation. However, as far as I know, if it is a collection agency, the CA must provide you with the proof that they have purchased the debt from the OC and the original signed contract between the OC and the borrower.
Are creditors obligated to show proof of a loan with signed papers or can they just say "I have verified your address"?
I have a specific answer for this question that is 'Yes'.
Creditor needs to clarify that he owes your debt and should show all the proofs related to the validation of the debt.
Yes they need to show the proofs, that's the final answer and one should not fall pray to the tactics of those sharks.
If it is an original creditor, they may send you details of the outstanding debt amount and it will be considered a debt validation. However, as far as I know, if it is a collection agency, the CA must provide you with the proof that they have purchased the debt from the OC and the original signed contract between the OC and the borrower.