After taking part in and purchasing a token on presale, in case the soft cap was not reached, in order to withdraw your contribution you'll need to wait until the presale has ended.
In this case you can withdraw your contribution (BNB/ETH/KCC/AVAX) by clicking on the “Withdrawal contribution” button.
MetaMask will now ask you to confirm the transaction. It will also show you the fee that you are required to pay for that transaction. If you agree, then click on the “Confirm” button to finish the process.
You will see a popup at the bottom left hand corner like this:
Check the balance of your wallet to see if the BNB is back (or MATIC, FANTOM, ETH, depending on the pool).