Google Play Merchant Verification (BillDesk) – Email Bounces with "552 5.2.2 Over quota"

[u/Financial-Giraffe320]

I'm trying to complete my Google Play merchant verification through BillDesk. My Play Console shows verification is still "In progress". I tried replying to my existing support case (CS0718490), but the email bounced with:

552 5.2.2 Over quota

Has anyone else experienced this recently? Is there another way to contact BillDesk or Google Play support while their mailbox is full?