1st Samuel 28:3 tells us that Samuel was dead. Further in that chapter the Bible tells us that Saul went to see a medium and ask her to ‘bring up’ Samuel. In 28:16 it tells us that Samuel spoke to Saul through this woman, she said she saw him coming up out of the ground. Wasn’t Samuel a man of God? Fortune telling and mediums are condemned by God, why was this practiced being used by His men?
Yes, this practice was forbidden. Saul was being rebellious here, and God apparently allowed Samuel to speak with him to inform Saul of the judgment about to be imposed against him. The Kingdom had been given to David, and the next day Saul and his sons would all die in a losing battle with the Philistines.