It is good advice to say that whether a CSA responds to your mails or not, you have to keep on communicating in the hope that he or she will respond some day. It may be that the CSA is having some peculiar problems. It may also be that the CSA is a tire kicker. I still maintain that it is safer to continue communicating. There should be nothing like giving up. It is like pouring water on a stone hoping that it will soften some day.