A sale, the register and a disputed payment

A seller and buyer sign a contract for a parcel in Korea. The buyer pays part of the price and later discovers that the seller has not completed the promised transfer registration. The seller says that signing the agreement already made every legal issue irrelevant. The buyer wants to know whether to demand performance, claim repayment or pursue another remedy. A separate dispute concerns whether an additional payment was actually made, and the parties hold different bank records and messages. This exercise supplies no special contractual clause, protected third-party transaction or statutory exception. The learner must distinguish the substantive transaction, the real-right formalities and the evidential dispute without assuming that one conclusion settles all three.