Is it permissible for me to deduct the port charges incurred on the goods from the capital of my partner, which I committed to returning in full, after I advised him to withdraw from the company to avoid further losses?

Summary: If the partner agreed to sell his share to you for its original capital value, without any increase or decrease (Bay' al-Tawliyah), then you are not entitled to deduct any loss from the agreed-upon capital. If you disagree on the condition of deferring payment until after the goods are released, the word of the one who denies the condition (the partner) is to be taken, unless you have evidence to prove the deferral. Consequently, you are obliged to pay his full capital, and the money becomes a debt upon you if you are in financial difficulty. If there is evidence for the condition of deferral, then there is a difference of opinion among scholars regarding the validity of the contract in that case. It is most appropriate to present matters of dispute to the Sharia (definition) judiciary or to ask people of knowledge directly.