Hi, I'm trying to log in to my Instagram, but it says your account was compromised, change password. I can't change the password, because I registered with a Facebook account, I don't know my old password, Facebook automatically choosed a password. I can't enter forgot my password, Instagram directs me to your account was compromised page.
I'm sorry to hear about this. Here's an article on what to do if your facebook account is locked or disabled. Also, here's another one on how to reset your facebook password.
According to many Instagram users that have the same problem, the cause may be related to another app: the Followers app. They often encounter this problem after unfollowing someone on it. This may be because, in this case, the Followers app needs you to re-enter your password, which Instagram identifies as entering your password on a website designed to look like Instagram/third party app or, in other words, as a phishing attack.