They disconnect or deactivate without any intemation.
If you are using internet for some important work all of a sudden they will disconnect and send a message your account has been deactivated with some technical lines like due to sales reversal.
It is ethics to intimate before disconnecting. Atleast half day before to avail some alternative.
Very risky.
Also If they say they will give 100mbps
Will get 82mbps max. And even with 4 antenna router wont get good speed if you move 20meters.