It's not too late to become an academic achiever. If they won't accept you for your master of choice in economics, just try to get accepted for another, similar master in teaching universities (although even in such institutions quite often a 2.2 minimum is required). Once you are accepted for another master, work extremely hard try to get a distinction or at least merit, then people will look more at that than at your undergraduate third. Then, you can choose to apply again for a masters in economics, for a PhD or for a job in industry. Although the whole process will take another 1.5 years, you can only win if you work hard from now on.