Early pension withdraw, leaving Belgium.

Is it possible and if so, what is the required to do an early pension withdraw as one is leaving Belgium for ever? Not a BE citizen. Worked temporary, but was a resident in BE. Is there a certain time frame, such as if you worked less than X months/years and you were a resident, you can withdraw the pension deductions, even if it means paying a penalty for that?

What are the things to do, consider when leaving Belgium, again, non citizen.