What is the punishment for refusing reconciliation with the husband's sister, despite her repeated harm, lies, and desire to interfere?

If the request for brevity with the wife's sister is due to her lying and interfering in everything, then there is no harm in that, but it should be done gently. It is not permissible to boycott her for this reason unless her abandonment would deter her. She should be advised and forbidden from lying and interfering in what does not concern her, and honored because of her relation to the husband.