Welcome to the forums!
I'd suggest reading the following:
Common Abbreviations
Credit Scoring 101 - great for knowing what is in your credit score and to see how your score is impacted.
What Steps Do I Take - great for learning the repair process.
and Example letters - PFDs, GWs, DVs, etc.
The Fair Credit Reporting Act spells out how long something is to report, and that's 7 to 7.5 years for most baddies (e.g. charge-offs, CAs, judgments, etc.). The clock starts at the date of first delinquency (DOFD) of the debt. This is the date you first went late and never recovered. If you pull your free reports from annualcreditreport.com or buy your CRs directly from the CRAs, you'll find a drop off date for most baddies on your TU and EX reports. EQ won't list a drop off date but will list the DOFD. Know that sometimes bad OC accounts can turn good and report even longer (thereby helping your credit).
In tackling baddies, pull those three CRs first and list everything side-by-side. I'd aim for everything, though factor your budget into this equation. The links above will help in deciding what to do first.
Sometimes accounts fall through the reporting cracks. Certainly don't ask them to report. It could be that the 7-7.5 yrs expired. Some creditors will delete after they sell the debt, though I'm not sure how SM works. Maybe they fell off due to a dispute of some sort. Some creditors don't report to all 3, though I think SM does. There could be a few reasons why the SM isn't reporting.
