Blocking Spirits:

Put salt around your house/apartment. If you can, put it into all corners of your house. If not, as long as you have salt somewhere it is fine. I have always salt next to front door and on my altar. This prevents negative spirits from entering.
Put an egg next to or under your bed near your head. In the morning, break the egg into a clean class full of water. Keep doing this daily until the egg, when broken into the water, is clear, the yolk doesn’t get runny and there aren’t much any bubbles in the water. This cleanses the energy and removed negative energy.
Protect yourself, especially before going to sleep. You can ask your spirit guides to protect you, you can ask archangel Michael to protect you, or any saint or deity you feel close to. Command that “Only the energies and entities from love and light can be and interact with me and be around me. Everyone and everything else has to leave now in the name of God* and stay away. So be it”. (Assuring in the name of God is such a strong command it even works on demons)
During day, you may want to wear a protective amulet like a quartz stone.
Burn white sage in your house. This has energetic properties which rebels against negative energies and entities. You might need to repeat this process multiple times if the spirit is stubborn, but for majority of the causes this works with first try. This cleanses the energy and protects it, removing unwanted spirits and energies.
Do a meditation where you cut cords. See yourself in your mind and watch if you see any cords, chains, robes, ribbons etc. being attached to your body. When you do, cut them off with your imagination. They can melt away, they can snap in half, they can be cut by scissors, a sword, a chainsaw etc. You might need to repeat this multiple times. This cut ties to your past and whatever you are carrying with you from the time you were dating your ex.
Turn to archangel Michael for help. You don’t have to be religious or even believe in his existence. Ask him to cut cords and step in, to speak with the mother and tell her to leave you alone. Ask him to protect you when you go to sleep. Archangel Michael is an extremely powerful and forceful spirit who can protect against any spiritual and physical entities. Nothing goes pass him.
Command the mother to go away and leave you alone. This is important. be firm and say you have nothing to do with this and tell her to go to the light. Ask archangel Michael to guide her towards the light. No spirit can interact with us when we command them to go away. They can be stubborn and might need to be commanded to leave us alone multiple times, but eventually they do. Even demons fall into this command when being firm and consisted enough.
Ask your guides or other loving spirit to take the mother away. They must help you.
FORGIVE YOURSELF AND LET GO. You have done nothing wrong and are not responsible for anyone else but your own happiness and needs. Guilt keeps us connected to things and people we don’t want to. It also weakens your energy and allows this mother to interact with you and guilt trip you. Feeling down and depressed and scared feeds these negative spirit, so you also cut the mother’s energy by being nonchalant about her demands, concentrating on your own happiness and be jolly. Seek out therapist or online help to let go if needed.
If THESE together when used long enough won’t help, then call in a professional medium/witch/shaman/priestess/priest who can perform a house cleaning and if needed, guide the mother to light (as she has not crossed over yet).
Source: niuniente