Is it considered unjust for children to confront their stepmother for relaying information about them, and what is the solution to this problem?

Speaking ill of people in their absence is either backbiting (ghibah) or slander (buhtan), as the Prophet, peace and blessings be upon him, said: "If what you said is true of him, then you have backbitten him; and if it is not true of him, then you have slandered him." It is obligatory to verify what is reported about the stepmother, for Allah, the Almighty, says: "O you who have believed, if there comes to you a disobedient one with information, investigate." And whoever conveys such news may be a slanderer (nammam) seeking to cause mischief. If what she said is proven true, then it is obligatory to advise her gently, and maintaining ties with her is part of maintaining ties with and honoring the father.