Law on Obligations and Contract

1. The President declared a state of emergency due to covid-19 pandemic and the prices of basic commodities are fixed by the government. Suppose you bought kilos of rice and paid an amount beyond that which is fixed by the government, can you recover the excess amount that you paid with legal interest?
2. A owes B P100,000, secured by a real estate mortgage. On due date, X without the knowledge and consent of A paid B the whole indebtedness, which B accepted.