I think i know what might of happened to your sub, if it's a dual voice coil you might have just blew out 1 voice coil. I had a similiar problem when i owened an infinity 12' aswell mine actually also went out but i didn't try pushing it down like you did. But i took the sub to a friend who knows alot about subs and he just rewired it using 1 coil and it worked not as loud as using both coils, but hey it worked good enough. So, you should take the sub out the box and see what it looks like and maybe you could google on how to re-wire it with one coil, hope the info helps.