Deathadder V2 Pro Connectivity Issue

Not much to say expect my new mouse wont connect via the wireless dongle, been searching up everything I can think of for hours and nothing has worked. I'm not even able to put the mouse in pairing mode via pressing the 2 side buttons and the dpi up button at the same time. I'm truely lost and I'm not sure what there is to do as everything I've seen has told me that it should 'just work'. I'd rather not have to return the mouse so I hope someone can please respond to this. Thanks