Sprint Genmar bar risers

any one know where I can get replacement chrome caps for the Genmar risers for my sprint st or even have a set made. I 've mailed Genmar several times over the last few months even begged they at least answer my mail but to no avail. Suppose I am not spending another £90 pound so they don't care. Bad bad customer service from these people and they will never again get my trade.