Tried helping it with silicone wd40 but the mechanics still seems rigidly jammed. Anyone has a clue on how to fix this?

is the button stuck in? that happens to mine sometimes. if not you can get it undone by jamming a screw driver into it in just the right spot usually. then to get it to undo you can slacken the 3 bolts off a bit and slide it more so the little arm that pushes the lever can press it a bit more.. if that makes sense. it worked on mine!

Thanks but I figured out that the locking cylinder is broken. I can turn the key easily and press the button as well but the door will always open even if it supposed to be locked... so I will order a new locking cylinder. That means I will have to carry a second key with me...