I got mine through Wiggle, and havign had the same problem, complained to them about it having broken, and they sent me a pair of new guards. Try contacting you bike seller, and pointing out that its not fit for purpose sold, and that they should contact charge about it. Charge should then send them new guards for you.
It is a known problem on the Grindr guards though.
Who did you buy it off of?
I got mine through Wiggle, and havign had the same problem, complained to them about it having broken, and they sent me a pair of new guards. Try contacting you bike seller, and pointing out that its not fit for purpose sold, and that they should contact charge about it. Charge should then send them new guards for you.
It is a known problem on the Grindr guards though.