If removing the third party apps work in removing the Action Blocked message, then make sure to not use them again.
Any of these steps should be able to help you in knowing how to remove the action blocked message, if these fail in removing the message, you may always try to simply wait out the time limit for the action blocked message to go out by not using the Instagram app for a few days.
Other way you might try to overcome the Instagram action block message is by linking your Facebook account with your Instagram account, this may help in letting Instagram know that you are not a robot.
If you have any questions, make sure to comment below!