Mr. A signed a contract to buy a 120 m2 apartment on the 12th floor of a 15-story apartment building project invested by Ltd Company Vina Construction. When he received the house, Mr. A was surprised to find that his apartment was on the 12B floor of a 19-story building. It is on the 13th floor of the building. Mr. A complained to the investor about the location of the apartment and was required to move to the 12A floor or the upper floor. Nonetheless, the investor disagrees and alleges that Mr. A's apartment is still on the 12th floor. The apartment purchase and sale agreement between Mr. A and Vina Construction did not specify it is on the 12A or 12B floor; thus, the company has the right to arrange this apartment on any 12th floor. Moreover, all usable areas and functions of the apartment on the 12B floor remain the same as described in the contract; Therefore, Mr. A has no right to require the investor to change the location of the apartment.

Mr. A is very angry with Vina Construction’s reply and wants to seek legal help.

As Mr. A's lawyer, please advise Mr. A on the following issues:

1. Does Ltd company Vina Construction breach the contract signed with Mr. A? If so, what are the violations?

2. Which of the following ways should Mr. A choose to protect his rights: (1) Negotiate with Vina Construction on how to resolve the dispute, (2) Sue this company to the court to ask for the exchange of the apartment location or demand the company to return the money he paid to buy the apartment?