IT could be. Every teacher has a contractual duty to communicate with parents concerning the progress of their children and normally that includes face-to-face meetings as well as written reports.
If this situation has been caused by intimidation, harassment or a personal quarrel, then efforts should be made to put matters right, using an intermediary if necessary. If you are satisfied that there is no justification for this teacher's stance, you have the right to direct her to carry out her duty. If she still refuses, then you should consider disciplinary action. She, on the other hand, is entitled to use the grievance procedure to defend her position.