# Posing armature causes mesh to stretch

I've gone through multiple different 'fixes' trying to get these shoes to not stretch like this when my model is posed, but I've had no luck. It's parented to the armature, the weights have been set like everything else on the model, I've tried applying scale via shift+A > Scale, but no matter what I do, the mesh ends up like this. It doesn't happen to any other part of the model.

There's no feet on the model that could be causing problems. The laces on our right are actually attached to the shoe model whereas on the left they aren't. I can't really think of much else I can do - it's probably a simple solution but unfortunately I'm rather new to using blender and can't figure it out. Anyone know how to fix this?