I would recommend inviting a Tibetan Lama in to do an appropriate puja. If that's not possible, any Tantric/Vajrayana practitioner who has demonstrably accomplished mantra siddhi. IME, the issue is power, i.e., having the power to make mantra and puja work as intended. Within Tibetan Buddhism, there are all sorts of pujas and practices for dealing with the eight classes of spirits. But you need someone with real power. Otherwise, you might make the situation worse.
Many people have some degree of power, and I have been study my own power for a long time, esoterically. Although there is no chance of getting a lama to come. I am especially talented at using the power of others around me, and for this reason I will include them. Wisdom is key and power is the door. What do you mean by eight classes of spirits
When Trisong Deutsen was trying to establish Buddhism in Tibet, He first invited the monk Shantirakshita. However, although Shatirakshita was a pure monk and a great scholar, He didin't have the power to overcome the demons of Tibet
. So He then told Trisong Deutsen to invite the Tantrika Padmasmabhava to Tibet, that Padmasambhava had the kind of power necessary to deal with these demons
. Trisong Deutsen did this and the rest is history.
These Tibetan demons, are they referring to asuras, or is this demons like "spirits," for example. I'm very curious about that knowledge, and the "eight classes" you mentioned. Also, I should point out I have affinity for dealing with "demons," as we call them in my circle, or bodily spirits in other words. These are utterly irrelevant from asuras, of course--asuras being living beings with their own consciousness and physical form.