I have had some problems with them, too. About 2 1/2 weeks ago I recieved an e-mail from them stating that I was a runner-up in their shopping spree sweepstakes. It said that 500 award miles should be in my account. Well, when I checked my account the 500 miles HAD been credited, but were also subtracted on the same day! I e-mailed them at 2 separate addresses and received the the usual "we have received your e-mail and someone will be contacting you" responses from both. It has now been over 2 weeks and noone has contacted me.
A newer problem: I made a purchase from Discovery Store.com basically because the site stated that you would earn 500 pts. Well I just noticed that the purchase has been credited- with 2 award miles per dollar, not the 500 pts promised. I guess I will try calling now, as noone seems to be having much success with the e-mail situation!
That said, I have never (before) had a problem with points being credited. I have made several other purchases through them, and was always credited eventually, although it sometimes took about a month. I am only a little shy of getting my $50 gift certificate, and then I'm quitting!