jspresso

i just put a spoon lower tie bar on my 94 eg coupe and when i took the bolts of to put the brackets on and all went fine then a feew months later i hear creeking noises because the nuts that are tacked onto the brace inside broke free from the welds and the only way to get them out is if you cut a hole to get a wrench in there to hold the nut, so my dilema is,
is there anyway you can get that nut to stop spinning to get the bolt out? without ruining the brace or can i replace the lca and brace cheap