You can request a refund based on your instance type:
For more information, please see Refunds.
Yes. If you stop using pay-as-you-go resources, please terminate them as soon as possible to avoid further fees.
TencentDB for MySQL offers a certain amount of backup capacity for free based on the region. The capacity is equivalent to the sum of the storage capacity of all high-availability edition and finance edition instances (including source and disaster recovery instances) in the region.
Excessive backup capacity will be charged at 0.000127 USD/GB/hour in the Chinese mainland. For prices for regions outside of the Chinese mainland, please see the TencentDB for MySQL Price Calculator.
To reduce backup costs, please see Suggestions for Reducing Backup Costs in Backup Space Billing.