You can submit support tickets as often as needed. There will always be a response, and if your issue is covered by your plan, it will be handled in a timely manner.
We do not provide hosting directly, however for any plan above the essentials plan, we are happy to maintain a hosting account on your behalf. We work with several premium providers.
We work with agencies all the time. We do not white label as we prefer to be transparent, but we support agencies and their clients so they can focus on business without getting caught on website issues.