Bought a underwater after 2hrs of use the battery's ran out ?

Question

when i put a brand new pair of battery's in it runs the battery's out straight away i then tried again and it did the same i switched it on took a pic then it switched it self off.

Answer 1

Sounds like it might not have been water resistant enough.  You may have a short circuit which is instantly draining the batteries.  The diagnostics probably detect this and do an instant shut down.  Take it to the shop and have them check it out.