How do you know that was not Samuel? Look at what Samuel says in the verses:
"15 And Samuel said to Saul, Why hast thou disquieted me, to bring me up? And Saul answered, I am sore distressed; for the Philistines make war against me, and God is departed from me, and answereth me no more, neither by prophets, nor by dreams: therefore I have called thee, that thou mayest make known unto me what I shall do.
16 Then said Samuel, Wherefore then dost thou ask of me, seeing the LORD is departed from thee, and is become thine enemy?
17 And the LORD hath done to him, as he spake by me: for the LORD hath rent the kingdom out of thine hand, and given it to thy neighbour, even to David:
18 Because thou obeyedst not the voice of the LORD, nor executedst his fierce wrath upon Amalek, therefore hath the LORD done this thing unto thee this day.
19 Moreover the LORD will also deliver Israel with thee into the hand of the Philistines: and to morrow shalt thou and thy sons be with me: the LORD also shall deliver the host of Israel into the hand of the Philistines."
The prophecy of Saul and his sons falling in battle with the Philistines. Even the previous reiterated message that Samuel told Saul in Vs 17
How can you ascribe that to evil?
God even says in Dueteronomy 18:21-22:
"21 And if thou say in thine heart, How shall we know the word which the LORD hath not spoken?
22 When a prophet speaketh in the name of the LORD, if the thing follow not, nor come to pass, that is the thing which the LORD hath not spoken, but the prophet hath spoken it presumptuously: thou shalt not be afraid of him."
Basically if the thing prophecied comes to pass then the prophet is of God.
We know that Saul and his sons died in battle, therefore, what the resurrected Samuel said came to pass. So how can you say that was not the prophet Samuel and that it was evil? God's ways are mysterious. He can use any means of communicating with people for them to listen.
Proverbs 26:5 says: "Answer a fool according to his folly, lest he be wise in his own conceit." I think this is what God was doing to Saul.
The witch was a scam she had no power to resurrect the dead and she knew that, when she saw Samuel she was alarmed because that could only be the power of God. That witch is a perfect representation of the mediums that exist today who trick people into thinking they can speak with the dead and they can't.
I agree that the dead cannot communicate with the living that is why I said he was temporarily resurrected just to deliver the message.
Even Lazarus was temporarily resurrected in a sense, he was not immortal so he would have died afterwards.