Thank you for your follow up. You've encountered a challenge with the third-party tools that are integrated with Canvas: who provides end user support? Though the Instructure Community is a place where we talk about Canvas, lots of us have questions about third-party tools (like you do with Unicheck). I looked at the Unicheck support site linked on this page and found a guide for students:
https://support.unicheck.com/hc/en-us/articles/360016436734-Student-s-Guide
This page answers your questions on how to view feedback and download it in PDF format, which you can print.
If you need help with accessing this guide or getting support with Unicheck, the best people to ask are your professor or your college's tech support team for students. Since you shared having a disability, your college's disability resources should also be able to help.