Im glad to see that you got it all sorted out. That's the thing, you don't HAVE to have company A's o ring in the thing, oh they'd love you to believe that so you only buy it from them at insane prices, but typically general parts, as long as the replacement is the same material and dimensions, it will work. As mentioned there are shops all over the place in most large cities, even smaller ones that sell this kind of stuff.
Aaron