Castle Lager Beer

The state of our local, National beer (Castle Lager) doesn't seem the same anymore, worst part is that its our favourite, after having changed from buying from Eikenhof, Kibler Park and trying Mulbarton, the results remain the same: the beer is none active , after opening/ pouring it foams up a bit but there is no, normal beer bubble activity, that you may obviously see in a beer, it remains until it seems to be like golden water in a glass, so this really makes one wonder if the fermentation / production is still the same or has the beer expired or what, please help and advise as to why and how....