@pherophuc other than offering sympathy I would suggest that we would need rather a lot more details of your issues to offer any suggestions.
Why can't you get an attendance report, an error or is it disabled by Teams policies in your tenant (it's in the meeting policy called Engagement Report).
Why can't people join a meeting, what happens? How to reproduce.
This is a community support forum, if you want to talk to Microsoft please raise support tickets from your Office 365 Portal.
