We've been sending letters to my daughter everyday that we can, but we just got a letter from her saying that she hasn't gotten any letters from us. We've been traveling, so we've mailed letters from CO, KS and TX. My parents have sent her letters and she's gotten those, and we all have the same address for her. We're not including anything that we shouldn't. They are just letters. How do we find out what the heck is up with her mail?