The law requires creditors to report to the CRAs what the DOFD was. Unfortunately, the CRAs are not required to include this information in your CRs. Pretty frustrating, huh?
I saw an EX report recently that specifically included the DOFD. For TU, if it happened in the last 2 years you would see it in the 24-month payment history (OK OK OK 30 60 90 ... it's when "30" happened, provided you never were "OK" again). EQ lists balance history for 2 years also.
Sometimes you have to ask yourself, "self, when did my life start to mess up?" and then you remember what month/year everything started getting unravelled and you couldn't pay the bill.
The Date of Last Activity may be the the last date you made a payment, and so the DOFD would be the next month. However, some of those scummy CAs reage the account to make the DOLA the date they got the account assigned to them. The DOFD never has anything to do with the timing of when an account went to collection or what the collector did.