If http://push-test.mattermost.com is working for you, please continue using it. While there's no service level agreement, it's important for us to keep running it so people can test out the full system.
Regarding a paid service for commercial companies who want an SLA, there have been other requests for this and we hope to offer it soon. You can join the Mattermost Insiders mailing list to be alerted when it arrives.