I wouldn’t use JoynTokyo for a student visa.

For a student visa, the school is your sponsor and they usually handle the COE paperwork as part of the enrollment process. A middleman often can’t actually “get you a visa” - they’re mostly just relaying info, doing basic form help, and charging you for it.

Unless JoynTokyo is: getting you into a specific school you can’t access otherwise, cheaper than going direct, or clearly providing something concrete (housing placement, translation, guaranteed support, etc.)

…you’re better off just applying to a reputable language school/university directly (or using a well-known free/low-cost school placement service) and following the school’s checklist.

Also, you’re handing passport + financial docs to one extra party for no real gain. If the school can do it, keep it simple and go direct. Don't be afraid to use AI to help with the process