G.R. No. 182819 - Bulawan vs. Aquende

On October 22, 2010, Antonina S. Sosa filed a complaint for the disbarment or suspension of Atty. Manuel V. Mendoza for alleged violation of Rule 1.01 of the Code of Professional Responsibility due to non-payment of a debt.
By Resolution dated April 18, 2012, the Supreme Court referred the case to the Integrated Bar of the Philippines (IBP) for investigation. On May 11, 2013, the IBP Board of Governors adopted with modification the Investigating Commissioner’s report, recommending suspension for six months and the return of the loan amount with legal interest. The IBP’s resolution was transmitted to the Supreme Court on December 10, 2013.

On July 28, 2006, Ms. Sosa loaned Atty. Mendoza ₱500,000 at an agreed interest of ₱25,000, payable on or before September 25, 2006, with a 10% monthly penalty for default. Mendoza signed a promissory note and issued a postdated ₱500,000 check as security.
Mendoza failed to pay on the due date; the deferred check was eventually dishonored for insufficient funds in October 2006. After a demand letter dated January 11, 2010 (proven received), Mendoza did not respond or settle. He filed motions and, in a January 10, 2012 brief comment, admitted the validity of the obligation but claimed—without proof—that he only received ₱100,000. At the IBP hearing on August 16, 2012, he admitted having ₱600,000 on hand yet still failed to pay.

Whether Atty. Mendoza’s deliberate failure to pay the loan constitutes gross misconduct under Rule 1.01 of the Code of Professional Responsibility.
What disciplinary sanction is appropriate for such misconduct.
Whether a disciplinary tribunal may order the return of the debt in an administrative proceeding.