From your description, I can't quite visualize what part is broken. A photo would help. If it is the elbow that is broken, you can buy one of those on Amazon. The elbow component is the same for all F20 and F30 masks. Or you can buy a mask there too. Or, with a picture, maybe someone here will have...

Hiya! I am on this bit of a journey to seek out temporary fixes on busted equipment until an replacements arrives, and bumped into this forum! While I didn't find any talk about these type of situations (hope I'm not going against the rules that I'm unaware of) :| So, long story ahort, My AirFit F20...