FDCPA 809(b), which is the statutory basis for debt validation, does not impose any requirement that the debt collector provide any documentation to support their finding, or to "prove" the validity of the debt.
The courts have generally interpreted a statement as sufficient, without any need to provide proofs.
However, there are a couple of federal jurisdicitons with pertinent case law that does support some level of documentation.
Ultimately, what is or is not adequate validation is subject to interpretation of the FDCPA, which can vary from judge to judge and jurisdiciton to jurisdiction. In most jurisdictions, what they have sent would likely be considered more that required under the statute.
However, there is no requirement under the FDCPA for a debt collector to ever send validation, and there is no required period for any response. If you wish to contest the adequacy of any validation, you are asserting that the debt collector remains under a cease collection bar, provided that the DV was timely. Thus, there is no violation of any provisions of the DV process by lack of adequate validation unless the debt collector resumes active collection activities, and then the issue would be of their violation of the cease collection bar, and not of the adequacy of their response.
