Stone_Hardgod: That tweet is from
December 17th, 2021.
Cananas: Sorry, but I don't get this answer. Do you mean many time has passed from that tweet? Well, we really don't know when Myst (2021) was removed from our accounts, you know....
I send an e-mail to Cyan support for clarification and asking for Myst (2021) being restored to my account. I don't know if this a Cyan or GOG fault.
I bought the Myst Complete Collection on August 26th, 2021 and it included Myst (2021), but after that, as I realized thanks to this post, it was removed from my account. By that time, August 2021, Myst (2021) and Myst Complete Collection were released on GOG (you know, even that tweet is from December 2021...)
The Myst Complete Collection included Myst (2021). You can check it on WaybackMachine:
https://web.archive.org/web/20210828092206mp_/https://www.gog.com/game/myst_complete_collection PS.: You have to copy&paste the web address above in order to see it properly from the wayback machine. If you just click on it, you will go to the current Myst 25th Annyversay collection (that I never bought)
GOG Support can investigate why the game you purchased on your GOG account is not appearing anymore.
Cyan cannot access your GOG account to solve this missing game issue.
Be sure to provide GOG your proof of purchase for that bundle, and they will be the ones who can investigate and resolve this for you.