This is a different case then was I was thinking of but am still not sure if this is a probation offense either. It sounds like poor communication from the buyer's part. For me, I try to buy a few issues to save on shipping so perhaps, he was looking to only purchase the two together. I agree that you should start a new PM thread and see if you get a response. However, if another buyer comes along in the meantime, I wouldn't feel that the book is on hold.
Shipping not an issue, both books CGC certified, both $100 & over.