I learned one thing from CACH LLC. They are very quick to accept PDF only if you attach with the request a FDCPA violation committed by their representative.
Document violations, then send it to their compliance department CMRRR. Demand that a reply be sent to your gf within 7 days. It worked for me.
I got out of collection, got myself deletion, and a decent amount of $ as a settlement. They only asked me one thing in return, not to SUE them by signing a release of claims.
By the way, I dont think CACH, LLC collect debt by themselves. I think they only buy accounts and hire law firm or independent collector for them. At least, that was my case.
Goodluck to you and your gf.
I thank the people here in myfico forum for their advices. They all rock!