Login issues, jetpack not working, small system errors

Hello, I have a big issue. Yesterday I had an issue with profile builde giving the critical error (not resolved yet). After that, my web 366dnizakatrem.cz had working jetpack plugin which how has an error during setup so I cannot set it up again which means I also cannot access that web (or add it at all) to this wordpress.com account. I am desparate of these things happening andI dont know how to resolve it. Also that web was bought via wordpress.com businness plan so I would need to get my FTP credentials which I also dont know where to find at all.. Can you help me somehow? :/

The page I need help with: [log in to see the link]