The downside to calling is it might remind them they should report.
However, calling and asking might persuade them not to report.
Having some bit of leverage is the key to winning a negotiation. The one angle I can think of is to call and offer to PIF the remaining balance of $1,370.10 (or thereabouts) in exchange for an agreement not to report. However, since they hold virtually all the cards, you'll need to proceed carefully and step lightly. Demanding something in writing could backfire and lead them to say, "Just keep sending in payments, and thanks for reminding us to report this to the CRAs."
If you've paid on-time, odds are somewhat increased they will be amenable to not report.
Who's the law firm? I'll see if I can't google up something on them.