My handheld GPSmap 76CSx won't load up./var/folders/ps/3m5d2s3d1k31m3f

It loaded up at home yesterday but when I got out on the water it would not start up. It has fresh batteries. The back release is separated (see photo) but it didn’t seem to matter when it was working and firing up. Where can I take it for a look-see and possible repair in 33908 zip code?