Why is my GCash account not linking properly?

I have already linked my GCash acc before and was able to pay multiple times alr when purchasing on an app. But then last night when I tried to download an app it said that I needed to add payment method, i tried to link my GCash again but they won’t let me and said that it was already added to my payment method but it said failed on payment and shipping. I tried to add another payment method, phone number as well as different GCash acc but still they won’t accept >< PLEASE give me some insights 🥹🥹

[Re-Titled by Moderator]