Paid 3 AI Studio account getting false 429 "monthly spending cap"

Google AI Studio / Gemini Developer API. I am on Tier 3 and well below my RPM/TPM/RPD thresholds yet constantly experiencing 429 errors.

On another occasion I logged in and saw my account downgraded to Tier 1 causing service failure then move back on its own to Tier 3.

Models: gemini-3.1-pro-preview, gemini-3-pro-image, gemini-3.1-flash-image, gemini-3.1-flash-tts-preview

Can someone please help ? Attached image is from most recent False 429 events.

Account just dropped to Tier 1 by itself again.

Can I have please a guide how to connect to a real human that knows how to solve this issue ?

Now account back to Tier 3, this is not sustainable. Spoken twice to Google Support this week and refused to help on the basis there is no bug. Yet, few hours later my Tier 3 is restored by itself. I am expecting again in the next two days it will be bumped backed down and up with no real explanation from anyone as to why this is happening.

Sincere apologies for this issue. Please use this form to report sudden tier downgrades, our team will check it: Gemini API Tier Downgrade Report Form

Thank you for coming back to me, I have filled and submitted the form.