I received a collection letter from a law office hired by my ex-landlord. From the day I moved out to the day I picked up the certified letter from the post office is 32 days (not counting the date I moved out). I didn't receive any written notice directly from my ex-landlord stating damages and their amounts before receiving the collection letter.
Chapter 7 Bankruptcy Attorney
That would be the date of you signing for the certified letter.
I would not put too much emphasis on the 30-day period required by the Fair Debt Collection Practices Act (FDCPA). The statute requires that the debt collector give you 30 days within which to dispute the debt or request certain information. But you are already dealing with an Attorney. They will either sue you or not, at which time you can present all of your defenses (or attempt to settle). It may be helpful for you to dispute the debt, but they will almost certainly not go away.