What collection agency is NRS? Is that Nationwide?

I had a cell phone bill go to two different collection agencies. While I was making a deal with one agency the other suddenly started demanding money from me, calling me at work when I asked him not too. I went back to the first agency and asked them to resolve or I would contact the attorney general and then I get this letter from NRS that this account has been resolved. Not sure who NRS is, maybe Nationwide?