The branch company sued together.

Legal analysis: you can directly sue the branch company, preferably jointly sue the head office, which will bear the repayment responsibility and the branch company will bear joint liability.

Legal basis: Article 119 of the Civil Procedure Law of People's Republic of China (PRC), the prosecution must meet the following conditions:

(1) The plaintiff is a citizen, legal person and other organization that has a direct interest in the case;

(2) Having a clear defendant;

(3) Having specific requests, facts and reasons;

(4) It falls within the scope of civil litigation accepted by the people's court and is under the jurisdiction of the sued people's court.