Gemini API Billing Problem — Previous Balance Missing and Prepayment Required

Hello Google AI community,

I need help understanding a billing problem with my Gemini API account.

Previously, I added funds to my Gemini API account and had a remaining balance. Today, when I open the Billing page in Google AI Studio, I see this message:

“No prepayment method set up for this billing account. Prepay is required for this billing account.”

My billing tier also displays “Unknown Tier”, and I cannot find my remaining balance.

Could someone please help me understand:

  1. Why is my billing account asking me to set up prepayment again?
  2. How can I check whether my previous payment and remaining balance are still available?
  3. How can I restore access to my existing Gemini API billing account without making a duplicate payment?

I would appreciate clear, step-by-step guidance.

Thank you.