How can one get rid of internet addiction, and how does one atone for their sins after publishing bad posts on websites that many people have read?

Getting rid of internet addiction is easy, and it is aided by sincerity with Allah and frequent supplication, remembering that time and health are blessings about which a Muslim will be questioned, so he should occupy them with what benefits him. A Muslim should also associate with the righteous, and use the internet for what is beneficial, such as learning useful knowledge and inviting people to Allah. Part of perfect repentance from spreading evil is to strive to remove it and spread beneficial things.