It's no secret that Twitter can be a toxic online environment. Of course, you can block people, but that won't stop them from making a new account and harassing you again. If this has happened to you, it's a good idea to report the account. Although this isn't an immediate solution, the Twitter support team can permanently ban the user or even an IP Ban. When a user is reported for violating Twitter's strict Community Guidelines, the support team will review their account. If the offense is harsh enough, an IP Ban is implemented. Not only does this ban the users' account, but it also helps to ensure the offender does not make another account. While there are workarounds to this (meaning the user may find a way to make another account), it isn't likely you'll have an issue with them in the future.