Spells, hexes, charms, are quite real indeed, and can have real effects. Whoever tells you that they’re not real, or that believing in them is not Catholic, is plain wrong.
However, you can protect yourself perfectly against the effects of curses and spells by relying on the Lord. Pray, pray, and pray some more, especially when you feel a spell or curse or charm is operating on you. That very moment is when you need to pray. Whoever relies entirely on the Lord is immune to curses, spells, etc. etc. (But the stronger the spell and the caster, the stronger your faith needs to be too. If you have a strong spellcaster working magic or curses against you, you need to stand fast in your reliance on God, and not waver.)
Of course you cannot prevent the person from casting the spells and curses, but who cares if you are safe in God’s bosom. Eventually they’ll probably give up if they see it’s not working.