The Law on Obligations and Contracts by Hector S. De Leon

Explain or state briefly the rule or reason for your answer.

1. C(creditor) sued D (debtor) for of the latter's nonpayment obligation. D won the case on a technicality (i.e., not on the merits). Nevertheless, when C asked payment again, D paid him. Now, D demands the return of what he has paid claiming, he should not have paid C since he had no more obligation to C under the law. Decide.
2. M, a minor, bought a bicycle for P2,000 from N, who is not a minor. Under the law, the contract is voidable because M is incapacitated to give consent because of his minority. Give the situation by reason of which M cannot recover the P2,000 from N.