70-300 lens locked in 70mm position

Hi, I have a 70-300 DO IS USM and the lens lock feature will not let go; it’s locked in the 70mm position. My question to the list is this a problem that others have experienced with this lens? Is there a quick fix or is sending it to Canon the solution?

Update: sat here playing with the lock switch and it let go. The lens will now zoom to 300 but something is now rattling around inside the lens perhaps a screw???. I didn't drop it and to my knowledge no one else had either. Still wondering if this is something that others have had occur?

Yikes!

Haven't heard that one before but definetly it needs to go back to Canon for repairs.