In January 2025, A remitted PHP 150,000.00 to XYZ Corporation, believing she was contractually required to do so under a liquidated damages clause in their service agreement. In April 2025, A's lawyer reviewed the agreement and informed her that the liquidated damages clause was void for being contrary to law, meaning A had no obligation to make that payment in the first place. A formally demanded a full refund from XYZ Corporation. XYZ Corporation refused, arguing that the payment was voluntary and was made under a mistake of law rather than a mistake of fact, and that payments made under a mistake of law are non-recoverable. Is XYZ Corporation's refusal to return the PHP 150,000.00 justified? (Bar 2026 Syllabus)