I cross-threaded the lower female nut of the strut top-mount and can't get it out. Advice?

So I'm changing my car's front suspension (both shock absorbers and springs). When assembling one of the struts, I cross-threaded the female nut that holds the spring and lower part of the top-mount. The nut stays in place and holds the spring but I can't get it out now. Even with the spring pushing it won't get out.

Any advice? Thanks.