If you have taken a Microsoft Certification beta exam and haven't gotten your scores by the time the exam goes live (usually it takes six to eight weeks to get scored for a beta**) then you need to follow up with your test provider <edited per Andy's feedback>. They are responsible for giving you your results. While I'm at it, know that test centers should not charge you for taking a beta exam. I posted general info on betas a while back here.
**unless you happen to take 71-621 or 71-622, in which case it will take way way way longer than 8 weeks, because we are, for possibly the first time ever, re-running the betas. But don't take my word for it: Three Windows Vista certification exams get a rewrite