Leopold II himself never step foot in the Congo during the entire time he ruled over it.
If the rubber quota was not met, then the consequence was death. The Force Publique, who was Leopold's personal police force set in the Congo, was required to collect a right hand per successful kill. hands could've been collected by FP officers, or by the villagers themselves. Since bullets couldn't be wasted, hands were sometimes chopped off while the victim was still alive. Often times, when villages were expected to pay the different with hands, they'd attack other villages to gather hands.
At least 500 Chinese labourers were imported to work on railways in the Congo, but a majority of them either left or died.
