Replying to FKS Help

So I was waxing my skis, getting them ready for the weekend and I went to turn up my din a little. I have FKS 120s and the front din screws turned fine but the screws on both heel pieces won't budge. I thought they might be frozen at first since they sat outside a couple nights ago but they have been indoors for at least 48 hours and are still locked up. I have tried both loosening and tightening the screw but it won't move at all. And its like this on both heel pieces. Anyone got any ideas?