On a hosted platform where you don't have access to the site's vhost configuration, or some tool that provides such functionality not set up redirect from the user interface, you can't set up redirects. Besides - the manual is clearly accessible, under the new link right under the product page, so I don't see how this is some oversight on their end:
I never said the manual was not online, I simply verified Amir's assertion that he couldn't quickly find one. Anyone who has read this site knows that he is unwilling to spend much time searching around for such things, and I'm sure a lot of consumers are, as well, so I can't fault him for that.
I have NEVER seen a host where I could not set up redirects, but the method of doing so varies. (Worst case, one could use the paid version of Cloudflare to do it.) However, if such a host does exist, anyone moving an existing site would be be very foolish to choose them.
This may not be an oversight on Geshelli's part, and it in no way reflects badly on their products, or the company in general. However, it is certainly one on their developer's part, and I recommend they bring the issue up with them ASAP. Without redirects, they will lose all page rank for every previous URL that has been changed. That is a disaster from an SEO/SER standpoint.
This has gotten too far off topic. If they have questions, they are welcome to message me directly. I'll be happy to help or give advice. While I'm critical of their DACs, they are by all reports nice people and clearly fellow audio enthusiasts, so I would like to see them prosper.