Is the remaining 6,0 EGP for the engineer considered a debt that must be settled, knowing that he has not completed some of the agreed-upon works and refuses to hand over the remaining amount until repairs are made?

It is obligatory for the man to deliver the work agreed upon in the contract. If the defect cannot be repaired, and there was an agreement in the contract to deduct a portion of the payment, then it is permissible to deduct an amount corresponding to the defect, either according to the agreement or as estimated by experts. The remaining payment is a debt owed by the questioner to the man, which must be paid, and procrastination is not permissible. In case of dispute, the matter should be referred to the judiciary.