Teacher, are these sentences OK? Did I use "as to" correctly?
I am sorry to hear about your present situation. We will not mail any documents to you till we hear from you as to where you want us to mail the documents.
Your use of "as to" is okay. The sentences are okay.
Your two statements, however, are slightly inconsistent. It would be better usage to write, "We are very sorry...We will not mail any documents..."
[Just my opinion-no big deal]