So, this is where the pastor better have some ‘splaining to do. Saul calls up Samuel from the dead and asks advice from him? First of all I thought that wasn’t possible, and secondly, if it were possible, it can’t be a good thing. On the second statement first. You are absolutely right, if it is possible, it is not a good thing. As Protestants we do not have a veneration of the saints where we believe that we can communicate with the dead or ask favors or help from those who are dead no matter how important they were when they were living. The primary reason for this is because we are in direct communion with Almighty God who is omnipresent and omniscient so why would we need to go to anyone but God for help and direction? Trying to interact with the dead is a dead end (see what I did there)?
Now, the Bible is filled with examples where the dead interact with the living but we never see this either as a positive thing or as something that we ought to emulate. Moving within that realm is not only confusing to me but there is also an element of fear simply because I know that it is not something that God would approve. I would very easily call it sin, so it is best to stay away from it and not even try to enter into that territory.
Saul is in trouble because he cast out not only all the mediums and sorcerers, which is something he should have done anyway according to Leviticus 19:31 and 20:6, 27, but he has also cast out all the priests so he very simply on his own. Keep in mind that while Saul is trying to figure out if God is on his side, which He is not, David has become the head bodyguard for the Philistine ruler. Things are not going in Saul’s direction at this time.