Help with hardtop bolts just spinning and not backing out

I bought a track s2000 with an aftermarket hardtop. I went to remove it to replace the seat and harness but I could not get the bolts connecting the bracket to the hardtop to back out. They seem to just spin endlessly like the nut or whatever they screw into are loose.

Now that I did that the bracket is a little loose so I have no idea how to fix this or who to even take it to to help me fix it. The hardtop has a carbon fiber look but if I had to guess its fiberglass with a carbon weave top layer. 

I'm sure I not ther only one this has happened to so there has to be some solution to this out there. I was thinking of cutting the bolts off but then I wouldn't know what to do from there. Suggestions? 

Got an impact driver, or want an excuse to get one?

 This could of course just transfer your problem to "how do I put the escaped captive nuts back so I can have a roof?"

 Pics or an explanation might be helpful for figuring out access theories. Right now nobody who doesn't have an S2000 can help you on that front...

Here are some pics to add context.

I have tried power tools but the bolts just spin just like using a ratchet. 

Try putting some tension on the bolt while spinning it.  Maybe get a screw driver or something to pry between the bracket and hard top or screws and bracket. Then try to spin them out. 

What he said about prying to put some drag on the spinning hidden fastener^^

But also, there's an important difference between "power tools" and "impact driver." Because the impact driver turns in a series of sharp jerks, it can use the inertia of the hidden/spinning fastener to generate relative motion, which is something a regular rotational power tool like a drill doesn't do. That said, nuts are pretty light and if there's something like nylock going on that may not be enough to do the job. The prying thing is a good call.

Not visible from the pics, is it possible to unbolt the brackets from the car instead of from the top to gain the access you need?

Hmm, I didn't try my impact driver. I guess that is worth a shot. 

I did try using a screw driver to put tension on the bracket but that made no difference. I guess I'll give the impact a shot. 

Most likely there was a captive nut embedded in the layers of CF/Fiberglass that's now free.   You'll probably end up cutting out the area around it then repairing it with a new nut.   If you can cut the bolt off, you may be able to fish it out and then use a rivnut to replace it, but I'm guessing it's completely sealed and won't be able to fished out.

If you can cut the bolt off and there's enough room to shove it out of the way, fill the void with some expanding foam or something so it doesn't rattle and drive you mad, then use a rivnut or equivalent for a new threaded attachment point.

WonkoTheSane said:

Most likely there was a captive nut embedded in the layers of CF/Fiberglass that's now free.   You'll probably end up cutting out the area around it then repairing it with a new nut.   If you can cut the bolt off, you may be able to fish it out and then use a rivnut to replace it, but I'm guessing it's completely sealed and won't be able to fished out.

If you can cut the bolt off and there's enough room to shove it out of the way, fill the void with some expanding foam or something so it doesn't rattle and drive you mad, then use a rivnut or equivalent for a new threaded attachment point.

I wonder if melting in a heat-insert nut like with a 3D print could work...

Get some panel bonding adhesive and glue the new nut-sert in with that when you set it.

No need to make it harder than it needs to be.