help len stuck
Rubber band is a good idea. There is a special wrench or spanner made for stuck filters. If you use a pipe-wrench be very careful. Too easy to damage the filter or lens. Your local camera shop might help you out. You can try some temperature change, like putting it in the fridge, to see if the materials have different thermal expansion (could just make it tighter).
If you have a semi-soft rubber mat or cutting board you can see if pushing the filter flat against it give you some grip to turn.
If you have a semi-soft rubber mat or cutting board you can see if pushing the filter flat against it give you some grip to turn.






Try some piping pliers or a bench mounted vice if you have one. If it wasn't the right size there's basically no way it could have mounted.