My 3x3 is very floppy. I thought it was because of the tensions, but now I tensioned it, it's stiff and floppy. When I shake my cube it makes a loud noise from the corner pieces that are loose. When I disassemble the cube, the corner end doesn't "stick" to the edge piece. I didn't disassamble the cube alot so it's not because of that. I can't buy a new cube, so what do I do! I have an MFR3S2.