No credit card required
Browse credit cards from a variety of issuers to see if there's a better card for you.
I'd wait it out, but I'd also pull your CRs weekly at least from somewhere to keep an eye on them just in case something pops on. I would also do some ground research like looking up licensing info for the CA in your state (and theirs). And I'd also think of any possible OC that it could belong to, especially for baddies in which a recent CA fell off or stopped collecting (just in case they sold it to Calvary). I would also monitor your phones to see who could be calling and mail for the dunning of course. But that's as far as I would go. I wouldn't send anything until they report and/or send a dunning letter. As mentioned, nothing might happen. In my repair days, I had quite a few sniff around but nothing came of it.
Also might be a good idea to "Opt out" for awhile
IME, opting out doesn't prevent soft pulls by CAs. However, if the soft pull was the result of the CRA providing info to the CA after an event on your CR (e.g. mortgage pull, auto inquiry, added account, debt paydown, etc.), then in the next go around, the CA won't be notified and therefore a soft won't happen. Of course, they can pull anytime anyway, but at least they won't get any alerts.
When any party makes request for your CR, they must identify themselves and provide a reason that qualifies under one or more provisions of FCRA 604 as a permissible pull.
You have the right under FCRA 609(a)(1) to request directly from the CRA any information reported to your credit file, and the name of the party who reported it.
Send the CRA a request under FCRA 609(a)(1) for the reason presented that authorized the CRA to provide them your CR, along with the name of the inquiring party.
Requests under FCRA 609(a)(1) require the payment of a fee, which is currently $10.50, and proof of your identity, so include those in your request.