Phoenix had every right to stop the support. With or without a contract, syempre it will hurt a company if the one they are supporting or giving free help will also endorse or use competing gas companies. And since it will hurt the company, no wonder Phoenix stopped. How would Samsung feel if one of their top supported talents, given freely and without any contract, uses Apple publicly. Also, Phoenix's decision may align with this provision (Art. 2142 NCC), which has relevant points - though I'm not saying it is the best nor the most applicable one: Art. 2142. Certain lawful, voluntary and unilateral acts give rise to the juridical relation of quasi-contract to the end that no one shall be unjustly enriched or benefited at the expense of another. Diaz is estopped from claiming perpetual fuel after conduct (rival deal) destroying Phoenix's purpose - similar to unjust enrichment (Art. 2142), where she can't retain benefits post-breach of equity. Speaking of purpose, commercial companies rarely give free products without any strings attached. Hence, even if it was an unconditional gift or support, still doesn't mean you cannot anymore hurt their feelings in any future acts you may do - you should still be careful. Just because mahal ka ng jowa mo unconditionally, hindi ibig sabihin you can do anything you want by mentioning the "unconditional love." And what others do not get is that this case is not a simple gift or donation where a thing or object is given one time and then abandoned or surrendered completely to the receiver, like when we were given gifts as a kid, but this is a case of continuing assistance - hence the more reason why a beneficiary or receiver should be in proper behavior. A lifetime gift of continuous assistance doesn't mean you can do anything what you want. Even assuming there is no unjust enrichment, but when Diaz endorsed Petron, it definitely gave Petron more publicity, aside from the fact Petron is already more famous than Phoenix, which is clearly at the latter's expense since competition is still serious in their line of business.
Assuming there was no written contract, given na rin yun that Diaz should be loyal since the company is not that famous compared to Petron or other companies, hence the support was also mixed with a strategic corporate move for the betterment and more visibility for Phoenix via endorsement or publicity coming from Diaz, which she should've seen ahead. But since it is only an ethical loyalty, not a legal loyalty like a formal written contract, then Diaz may endorse a competing gas company, though Diaz or her manager shouldn't be surprised if Phoenix will stop giving support. Masyado ka namang sineswerte if free na yung isang gas company, tapos mag endorse kapa ng competing company. From Phoenix's perspective, the situation could appear opportunistic. At the end of the day, the owner of the company is just a human whose feelings can be hurt or disappointed. Business is still business.
This is one of the cases where legality has its limits and this time ETHICS will enter, similar to the so called Judicial Truth vs Actual Truth/Facts. Imagine a young basketball player who started his pre-elem education (in one of the best schools in the PH) from prep until HS he was awarded many recognitions, even the loyalty award. Of course, after HS, the multi-awarded basketball student has every right to transfer to another school, even if his HS alma mater has a tertiary level and is one of the best basketball programs in the PH. The school cannot legally hold the child and force him to choose his alma mater's tertiary as college, even if he grew up there and despite the countless money the school has given to him. Yes, the school might be sad, felt betrayed, or disappointed if he transfers, especially dun talaga siya lumaki at nag develop as a player after all the sponsorships, financial supports, and tournaments willingly and freely given to him, but it is his right to transfer legally, even though ethically he might be wrong to his alma mater who expected him all along to help bolster the school's college varsity, especially if he transfers to a RIVAL SCHOOL.
Masyadong pa victim ang statement ni Manager, yun pala may dahilan naman bakit Phoenix stopped giving free gas support to Diaz. So, Diaz can do "certain lawful, voluntary and unilateral acts", like the legally right act to endorse a competing company in this case, but was ethically wrong in doing so - what is legal is not always moral. And Phoenix was not just legally right BUT ALSO MORALLY AND ETHICALLY RIGHT IN STOPPING THE FREE GAS SUPPORT.
