Is Deliverance Biblical?

Is Deliverance Biblical?

Mark 6 vs 7&13

⁷ And he called unto him the twelve, and began to send them forth by two and two; and gave them power over unclean spirits;

¹³ And they cast out many devils, and anointed with oil many that were sick, and healed them.

1. When Jesus Christ sent out his disciples, their first assignment was to cast out unclean spirits, and the Bible also says that the disciples demonstrated the power by casting out the devils.
2. So, if Jesus Christ talks about unclean spirit and the disciples cast out demons, why are some people saying there is no demon or deliverance is not scriptural?
3. May God deliver such people from spiritual ignorance in Jesus’ name.