ProofHub is a cloud based project management software with features like gantt charts, proofing, reporting and custom roles. It's available for iOS and Android.
Pro Extensive customer support
A knowledge base is provided in their site for FAQs, use cases, and video tutorials. In most cases, the answers you are looking for are already addressed in this section.
The website also provides an Update Page to keep you informed about the latest features or issues about the software.
Their Facebook page and Twitter handle are active and responsive. You can communicate with them via their social networks.