REAL ESTATE

Hi Good Day!

My uncle bought a piece of land. He decided to build a restaurant out of it. The land surveyor, surveyed the land and had admitted that he committed a mistake. The problem is that my uncle had build a wall on the 7 sq meters on his neighbour's lot.

One of the owner (OWNER A) out of the 5 siblings of the lot had told my uncle she will sell the 7 sq meters for 300 000 pesos. I think it's overpriced considering the environment of where the land is situated. So my uncle then bought from the brother (OWNER B) of the owner of the lot, where we believe that 7 sqmeters is located.
Now OWNER A had filed a complaint, and will sue my uncle.

Though he had already bought the land from OWNER B where the 7sq meters is situated, who has the right for the lot/land now?

Does my uncle have the right over the land or that Owner A will have to sue Owner B instead for selling his part of land?

PLEASE RESPOND ASAP! THANK YOU!