If you believe access to your SoundCloud account has been compromised, we would recommend using the “Revoke all’ feature to revoke all access to your account. This can be found by scrolling to the “Connected applications” section of your settings, https://soundcloud.com/settings:
When prompted, select “Revoke all and sign out”.
You will then be signed out of all currently signed in devices. This action will sign out any attacker who may have gained access as well.
If you also believe your password has been compromised then please follow the steps outlined here.