One of the most frequently found problems with keys is that the lowest side key on the left hand joint gets bent upwards and then gets in the way of the next side key operating properly. The solution is obvious: Bend the lowest side key back into position. Here is a picture of how I do it.
With the left thumb, I am simultaneously depressing the key and putting pressure on the key that opposes the outward pressure that comes from bending the key back down with the pliers. Note: Use pliers without teeth, or cover the teeth with masking or duct tape.
The damage to the Eb/Bb side key can come from not knowing how to properly assemble the clarinet, or it can come from dropping the joint and it landing on that key.
I will try to add a picture of how to adjust the crowfoot key next.