Unfollow 20k on Twitter

I need to unfollow 20k people on Twitter ASAP. We automatically followed everyone back on this page but now it is too much and cannot use the page effectively. I want to unfollow them all and start fresh. However, I want to make sure that I do not do anything to put the account in jeopardy when unfollowing so many people quickly. Looking to unfollow the 20,000 people as quickly as it is possible without taking the risk of the account being flagged, banned or deleted.