Generally when a customer has issue with the maps not showing up they have accidently hit the Declutter option.
First check to make sure you have a device that has maps installed correctly. If your using a SD card for you maps please make sure the card is properly installed and latched. (the metal latch should close and gently slide down to lock)
If this does not fix your issue Please check your Declutter setting.
ALPHA Instructions to remove Declutter:
On the map page press the Three bars on the bottom, scroll down until you see Map Declutter Off, Press "map declutter off" and you shoud see your maps again. When you go back to check on the setting it should now read "Map Declutter On" which indicates that the declutter is actually turned off.
Astro 320 Instrucations to Remove Declutter:
From your map page press the Menu Button. Look for Declutter Map off, Scroll down to Select Declutter Map Off and hit Enter. Your maps should now be showing, When you go back to check that setting it should now read "Declutter map ON" which indicates that the Declutter is actually off now.
If this does not fix your mapping issue please call Double U @ 855-384-8687