I have had the same problem before, seems people are thinking its the post and screw, not the wire guide.
Cheddar is right, they flatten the end of the wire to get it to grab when they install, but that doesn't help much, and you would have to pull the other end, that is probably OK.
Also, I have seen this situation, where the wire is actually broken at the flattened part, and that piece is still in the PF.
That could be the case for you, not sure, but then there is nothing to grab the PF wood.
I think a "proper" fix might be to remake the wire, with flattened barbs to grab, possibly with a bigger wire.
That is scary though, and may require drilling the hole a little larger. Yikes!
Hope to see a better recommendation here.