If you don't have the answer to a question, tell the caller "Please hold while I go to get that information".  Or if you can't get it let the caller know you just don't know.  Some people may have a problem with that, but it beats lying or giving wrong information.

I have talked to csrs who had to put me on hold several times.  When they came back my tone was normal and they went the extra effort to resolve my issue.  A good experience is not just in the hands of the csr.  People call cs and are very angry and in sometimes insulting.  If a csr has had a bad day things can get pretty ugly really fast.  Just do the best you can and be honest.