If He is with us, error is not. But error is constantly appearing from jumped up, self appointed experts who think they have access to the truth, but don't. They have a long pedigree, beginning with the Arians and Nestorians. The heretics have been amongst us from the beginning, and it has been the ongoing job of the Church ("my" Church) to correct their errors.
So do the teachings about selling indulgences still stand?
What teaching? That such behaviour is sinful? The "selling" of spiritual goods has been consistently condemned, by my Church, since Apostolic times. So yes, those teachings still stand.
You really believe that? It was Simony and the selling of "indulgences" that sparked the Reformation in the first place. Pope Leo X needed money to rebuild Saint Peter’s Basilica, so he did what popes and bishops had been doing for 4 centuries -- he raised a fortune by selling indulgences. Leo X asked the famous Dominican indulgence seller, Johann Tetzel, to offer a plenary indulgence to those who donated funds for the reconstruction of the Basilica. That's a fact and there's no dancing around it.If the selling of "spiritual goods" has been condemned by "your church" since Apostolic times, then you must not be a Catholic. Either that, or you're believing bad information that's being fed to you.