Google Ads has introduced a new help page detailing procedures when accounts are paused due to suspicious payment activity. When Google detects irregular or unauthorized payments, affected accounts receive an in-account notification and an email.
To resume advertising, users must select “Answer questions” in the notification and provide payment history details. Confirmation may involve verifying payment methods; an email is sent within 10 minutes of submission or a decision is provided within five business days. Google may request a payment of either outstanding or system-determined amounts.

Additionally, payment verification includes a temporary $1.95 card charge, refunded within 14 days, with a decision provided within two business days of code submission.
Read the official announcement here: Ads paused for suspicious payment activity.
This update was spotted by Hana Kobzová.