Google 'How to get rid of Shadow people?' - lots of good ideas.
I agree with the above said- authority! Understand that you are stronger than them, they feed on fear and everything negative. Make your room clean and happy, they lose power if you feel happy and comfortable in your own home.
I've noticed they tend to pray on people who are on a lower wavelength at that point in life (or possibly it's as they say - You can not perceive what you are not the vibration of, therefore you can just SEE them more when feeling low). Such as going through a stressful period, depression or focusing on the dark a lot. Try to raise your vibration generally with whatever works for you - meditation, music, walk in the nature, time with friends, just sitting down and reorganizing life, think of God, listen to positive affirmations...
Use humor, make fun of them. My old dentist used to say that your mind can only fit one emotion at the time, so when you make a situation comical, there's no space for fear. I know in that situation it may seem hard, but it's just a step to make them feel your authority.
Even when you say the prayers, try not to do it fearfully, but with power, as if you KNOW you have the secret weapon and they MUST leave.