Philips DLP2113U/93 Type Powerbank Battery Started Draining Quickly

 purchased a Philips DLP2113U/93 type powerbank on July 1, 2023. For four months, I had no troubles with it. However, over the past month, the battery abruptly decreases from 30% to nothing, and even when it's at 100%, it soon falls to 50%. The two-year warranty hasn't expired yet, but I can't reach their customer care no matter how hard I try, doesn't matter,  I demand that it be either fixed or replaced with a brand-new item immediately. I have attached the invoice for reference, can provide it whoever needs. It's designed to be used under emergencies when there is no power supply available, but with this thing I keep looking for power supplies again.