Raylite Battery failing after 16 months

HI purchased a Raylite 636 battery from North Coast road battery centre on the 13.08.2013 and its now 16 months and the battery is now faulty. This is not acceptable as my previous battery lasted me almost 37 months. i see that another customer had the same problem at 16 months. Is this a common fault with Raylite? I am afraid to purchase any of there products now. I will be taking the battery to North Coast road and hope that they replace the battery for me at no cost. If not then Raylite has lost all my support and my family and friends. Raylite should look into this problem cause batteries should not last 16 months.