well I would if I was you contact the company, never know what they might send you?
and second, I would be thinking about switching heads as well, ir inspecting rest of heads I have real well for any dirt grease rust or what ever that might have caused them to not work properly
I have used both fixed and mec. heads and never had either one fail, but never used that brand, so cannot say much on them
but good mec heads these days to me are just as good as a fixed head and shoul;d work 100% of the time
good luck and again congrats!