Instance is suspended due to billing issues.

Hi,

My Google Cloud Sql Instance is suspended due to billing issues.

This is the log message I got from the Appengine Dashboard.

java.sql.SQLInvalidAuthorizationSpecException: epenpal-cloudsql:epenpal has been suspended due to billing issues.

I have read thru the pricing page below.

https://developers.google.com/cloud-sql/docs/billing

and I changed the plans from D8 into D1 package two days ago.

My understanding is the quota is exceeded, it will be charged at per use rate and 

I wonder why my account is suspended.

'Use of storage or I/O over the included quota is charged at the Per Use rate ($0.24 per GB per month for storage, $0.10 per Million of I/Os). The maximum storage for any instance is currently 10GB.'

since my serivice is growing, I wonder I have to change into per use plan or upgrade into higher instances like D2, D4, or D8.

I am using this service for my Android app, ePenpal and now it's not working.

Will it be back to normal tomorrow since it's daily charge. I'm kind of worried.

Any suggestion and comments will be appreciated and sorry for my bad English.

Thank you in advance.