If you want to download the source code of sensenet you can do it on GitHub.
There's also a Sensenet organization where all the Sensenet related
tools, components, documentation and other resources are listed.
Feel free to submit an issue or a pull request in the related Sensenet repo, we're eager to hear your thoughts, ideas and questions.
Share your feedbacks or quick questions about SenseNet components chatting with us on Gitter
Enterprise customers can submit issues or question directly to our core team through support.sensenet.com.
If you need vendor support for sensenet implementation or want to get custom development please visit our website and contact us.