Hi there, sorry I had gone offline by the time you had replied. First of all, going through your phone should be treated as a breach of trust and a potential disciplinary matter because she had no right to do so. However, now that she is leaving, it is probably unlikely the employer will take it any further.
As to the allegations against you, unless there are other incidents she can rely on to argue that you pushed her out, it is unlikely she can use this conversation alone. That is because she was not aware of it until she had already handed her notice in, therefore she cannot realistically claim it was the reason for her leaving. However, if there were already other incidents between you and her, then she could try and add the conversation as just another piece to the bigger picture where there was an ongoing campaign against her.
In any event, she is now leaving, and it is for the employer to decide how to deal with it. They can do nothing and just let her go on her way. Alternatively, they could consider investigating this and if they find evidence of wrongdoing, they can take it further such as disciplining you as well. However, as you have more than 2 years’ service, they cannot just dismiss you and they must show there was a fair reason for any dismissal and also shoe that a fair procedure was followed, otherwise you can challenge it as unfair dismissal.
Does this answer your query?