Removing liner'd tie-down?

for whatever reason the monkeys who lined my bed happened to cover the tiedowns, too.

I need to remove one to install an undercover swingbox but the sumbitch won't budge with my drill. I cut the crap off the bolt but still having no luck.

Any ideas?

 

My local line x guy told me to heat a blade to a high temperature and cut it. I knew my limitation so I took it to him to install my swing boxes.

 

Good idea, thanks. I may try to outsource this.