Hi, Kathy. There are 2 kinds of fiberglass resin, polyesther and true epoxy. The first thing to do is contact the surround manufacturer to find out which one was used. Also ask them, before you attempt any repairs if the breakage is covered by warranty.
If you get absolutely nowhere, there is something that you can try but I stress that it might not be successful. The caulk will not be, in all probability. So there is absolutely no guarantee on this but it is what I would do. Get some Bondo resin from an auto parts store or department of a major retailer and a cheap, small brush. Mix the Bondo and force it into the crack. Wipe it off quickly and work quickly because the Bondo will start to set up quickly but will take 24 hours to be fully hard. Don't try to sand off any runs or drips or you will cause more damage, but you can try polishing with one of the fiberglass polishes from the auto parts store if you need to and after 24 hours.