That looks like my lighter. I use the Xikar high altitude high performance butane. You do not have to press down hard and in fact shouldn't. You'll tear something up before long. Wiggle the nozzle around on the filing slot on the lighter to center it. Then press down for around 5 seconds.
The other problem you could be having is you need to bleed the lighter to vacate air. If the lighter is full of air, which is heavier than the butane, it won't accept any butane. Take the skinny pin on a pipe tool and press down the receptacle on the lighter. If there is stuff inside, you hear and feel it vacate the lighter. Then try filing it with butane. I've filled many a lighter with the butane you have with no problems.
If all that doesn't work, is always possible the lighter is screwed up. Send it in under warranty.