My Managed WordPress sites are getting 503 Service Unavailable Error?

I have two managed WordPress websites (http://writetogeather.com, http://giftsinonline.com) on GoDaddy. 

Suddenly all two websites getting down and error showing

- "Service Unavailable

HTTP Error 503. The service is unavailable"

Unable to contact support. I haven't don't any changes also last 7 days
Please advise.