All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
It is not permissible for you to obey your mother when she commands you to cut the ties of kinship with your paternal uncles and aunts because obedience to the parents (or any other person) is confined to that which is permissible and good. (Whatever constitutes disobedience to Allah is excluded from this.) Verily, cutting off the ties of kinship is far from being permissible or good; rather, it is one of the grave and most serious misdeeds.
The children are only obliged to obey their parents in what is permissible.
The fact that your mother fears that your paternal uncles and aunts may brainwash you, turn you against her, and negatively influence you does not justify her action of preventing you from maintaining the ties of kinship with them.
On the other hand, if your parental uncles and aunts were to insult your mother in your presence, then you should repel such transgression against your mother and forbid them from such a sin with kind advice. Anas narrated that the Prophet, sallallaahu ‘alayhi wa sallam, said, “Help your brother whether he is an oppressor or an oppressed.” A man said, “O Messenger of Allah! I will help him if he is oppressed, but if he is an oppressor, then how can I help him?” The Prophet, sallallaahu ‘alayhi wa sallam, said: “By preventing him from oppressing (others), for that is how to help him.” [Al-Bukhari]
As for reconciling between your parents, this is one of the great acts of kindness and dutifulness towards them. Verily, reconciliation abounds in good. It is unbecoming of your mother to reject people's attempts to attain such a good objective that is encouraged by Allah as He says (what means): {No good is there in much of their private conversation, except for those who enjoin charity or that which is right or conciliation between people. And whoever does that seeking means to the approval of Allah - then We are going to give him a great reward.} [Quran 4:114]
Moreover, Abu Ad-Dardaa’ reported that the Prophet, sallallaahu ‘alayhi wa sallam, said, “May I tell you about an act that is better and more rewardable than (voluntary) fasting, prayer, and charity?” People replied, “Yes.” He, sallallaahu ‘alayhi wa sallam, said, “Reconciliation between people, for discord is the shaver (i.e. it undermines religious commitment).” [Abu Daawood]
Lastly, we advise you to keenly implore Allah, The Exalted, to rectify your affairs and guide all of you to the right path.
Allah Knows best.