Devotees are always attacked by demons (of sinful desires born out of nescience), and we should not expect that our desires will disappear instantly. If we take shelter in our materialistic desires, we cannot expect to be protected from them. We must pray to the Lord constantly for freedom. Only Krishna can protect us. Krishna assures us that He will protect any devotee who surenders to Him.
Lectures from a disciple Vol 1, attachments and material desire, Pg 465-66