hi, hope this is the right forum for this
Bought one like this

Buy ZXC-01 Cree XM-L T6 910lm 3-Mode Memory White Bike Light - Black (4 x 18650)

, now I can't get it to work. I plug it in and it shows fully charged,i have another one coming to test it but with a volt meter shows full charge. When I plug it into the light, The on/off button shows red and it will only give me one level of light rather than three,very dim light, now i been trying to open it up to have a look might be lose wire or something ,but i am stuck how do you open these up ???
there's 2 holes in the bottom of pic , and not sure how to carry on from here ???
anyone?

heres the pic,


any help would be appreciated

ty