Can’t open the link you provide because of error, but from description your work is suited for CodeCanyon.
Keep yourself and your family in safe first. I think that buyers will understand. Wish you and all the others the minimum impact of this situation!
Same issue and when I tried to log in I’ve got some error.
You cannot change the quantity in “More items by…” section, but you can use html code and images in the item’s description to promote your other products.
You need to do it through support ticket. By e-mail you can be simply ignored, because reviewer is not obliged to answer.
Try to use another browser or upload via FTP.
You need to wait. They might respond in 2-3 days. But I’m sure they will help you.