The first problem — a chewed-away zipper bottom — is quite common, but requires no sewing to fix. As you’ll see in the video below, all it takes is a drinking straw, some hot glue ...

Do this on both long edges. Using the zipper foot, sew along the piping. Place another 3 x 9 rectangle on top with righ sides together and pin. Turn the pieces over so you are sewing on the back ...