New Co. Limited Liability Company (Ltd) has 3 members, Mr. A, Mr. B, and Ms. C. After 2 years of operation, Mr. A wanted to withdraw his contributed capital from the company to settle abroad, and immediately to sell all the capital contribution to Mr. D, an outsider of the company. The transaction was completed, but two problems arose.

1. Ms. C wants to file a lawsuit against Mr. A to ask the New Co. Ltd company not to recognize Mr. D's membership status. She alleges that Mr. A had previously promised to transfer the whole of his contributed capital to Ms. C. Both Mr. A and Ms. C also made a written statement signed by Mr. A and Ms. C, that certified that Mr. A received a deposit from Ms. C for this business.  

2. New Co. Ltd company also does not want to recognize the membership for Mr. D because he is the director of Binh Minh Joint Stock Company, a competitor of New Co. Ltd Company.

As New Co.’s lawyer, could you please provide legal advice on how to deal with the above situations?