We had guests at our house this afternoon and one of them walked into our sliding screen door as they were trying to get out onto the deck. It jammed immediately, but we got it to move enough for them to get outside. Since they left we've been trying to fix it but with little success. We can get the bottom to move quite freely, but the top won't budge. We've tried adjusting the screws at the top and that doesn't help at all. Any suggestions?