Experian Followup #2

So, the letter back from Experian states that the lender confirmed that it is my debt, and that "The FTC does not require that the consumer credit reporting company obtain documentation..." "nor does it require that consumer credit reporting companies act as mediators or negotiators in account disputes".

I'm debating whether to follow up immediately, again with the letter from the creditor stating they have no proof of that being my account, or whether to wait 90 days then follow up. I'm leaning towards the former, as the worst they can do is stop doing much about my letters. As this is the last thing I'm trying to get cleared, that might not be the worst punishment ever.