The first issue is whether or not your debt validation request was timely.
A DV request must be sent within a 30-day window after sending of their dunning notice in order to be timely.
However, even if the DV were timely, it does not impose any requirement to reply. It simply imposes a cease collection bar, which remains in effect until they choose to send validation. It also does not impose any requirement to delete the reported collection, so deletion was not part of the DV process.
Their reply may not be a response to your DV request, but even if it is, the issue would only be one of whether you consider it to be adequate valiation . If not, it is not aviolation of any provision of the DV process; it would only result in your assertion that they remain under a cease collection bar.
It is unclear as to the reason for their deletion. However, one possible reason is that the debt collector had their assigned collection authority terminated by the creditor, which under CRA reporting policy mandates deletion of any reported collection. That is unrelated to and separate from the DV process.
If they no longer have collection authority, that would explain both their deletion of their reported collection and their instructions to contact the creditor regarding any future issues pertaining to collection of the debt.
If the creditor has terminated assignment of collection authority to debt collector 1, it might forbode a new assignment to a debt collector 2, who may then immediately report their own collection without any prior notice.
