Hi Karen, the news is probably not good. Any time a liner is left empty it shrinks and dries out. It is probably not usable. If the liner has only pulled away from the wall by a few inches and if you can patch the hole you may be able to refill on a sunny day.

Here is a trade secret for finding holes. Remove two top rails, coping and rods. Crawl in underneath the liner. The hole will look like stars. Automatic cleaners can cause the liner to look like the milky way from the underside. If it is an isolated, patchable hole, you will easily find that also.

Best of luck, Dennis