Lending Tree — A company employee stole my information and I received a letter from LendingTree regarding this

First, I received an alert letter from LendingTree that my information may have been stolen. My major complaint at this time is that when I called them back and told them they sent the letter to a "David" Cantrell, but mailed it to me, Laura Cantrell at my address, they would not divulge any information to me about this person. I said, well I need to know if it's a typo or something worse. I do not know a David Cantrell. I asked for a supervisor, Jeff Moore x 7677 out of Charlotte. I employed, won't you work with me on this? This is pretty scary to me? Who is this David Cantrell using my address. They would not help me. The only advise they gave me was to look at my credit report. Well, this isn't letting me know if this David Cantrell is using my address, my good credit or anything else.