You are disturbed because of your vital ego. It is evident that your faith and attitude cannot be perfect, if because Mother makes other arrangements for her work, you at once regard her as unjust, false and tricky. Every sadhak ought to realise that the work given him is not his property—it is not his work but hers; she must be perfectly free to make an arrangement and to change it whenever she thinks right to do so. To challenge her action and demand an explanation from her or claim the work as personal property is an entirely mistaken and egoistic attitude.
Ref: The Mother with Letters on The Mother