Try the stripped footstrap plug repair suggested in
Products/Product Assistance/Repair Guide.
Here's the link:
If you think the FS plug is soft, it might be good to open the hole slightly and run a 6mm x 1.0 tap down the hole to maximize the surface area the Thread Repair 2 part epoxy has to work on.
If you use the suggested repair kit, you should have no future problems with FS inserts as the threads will be upgraded to approx. Gr. 5 steel.
Be sure to take a tooth pick and work some of the mixed but uncured epoxy as far down in the hole as possible.
The blue "release agent" will allow you to unscrew the FS screw after the epoxy sets.
Try to clean off any excess epoxy around the top of the hole before the epoxy sets.
The resulting thread repair will have significantly more thread engagement than you get when you screw a new FS screw into a new FS insert as the holes in the inserts are a little bigger than the root diameter of the FS screw PT thread.
Hope this helps,