Tier 1 Postpay silently switched to Prepay; "prepayment credits depleted" 429, never opted in

My Gemini API project was on Tier 1 Postpay and has been working fine. Without any action or notice from me, it has been switched to Prepay, and every request now returns:

429 RESOURCE_EXHAUSTED
“Your prepayment credits are depleted. Please go to AI Studio to manage your
project and billing.”

Details:

  • Google account: cl....@gmail.com
  • Model: gemini-2.5-flash-lite
  • Cloud Billing account: “Personal” 01FA0C-16B1BC-47… — open, active, in good
    standing (currency IDR)
  • Previous state: Tier 1, Postpay, working normally
  • Current state: AI Studio shows the project on Prepay with a depleted/$0 balance
  • Account active well before March 23, 2026 (existing paid user, not a new signup)

What I’ve tried: generated a fresh API key (no change); confirmed the billing account is open with no failed payments; confirmed the project is still linked.

What I did NOT do: I never opted into Prepay, never relinked or changed my billing account, and got no notification of any plan migration.

Request: Please restore my project to Postpay so requests work without a manual prepay top-up. If existing Tier 1 Postpay accounts were auto-reassigned to Prepay during the rollout, this looks like an error. Happy to share the project ID via DM.

did it get resolved for you?

still waiting for reply. Did you also have this issue?

I have no issue yesterday, it started from today where I got demoted to prepay.

Hi @claudio_aditya @naman_kaushik
Can you DM me your project Id and billing account id ?