Breach of confidentiality?

My partner was recently dismissed following disciplinary actions. I bumped into one of her old colleagues who had a lot to say about the matter and discussing information that was sensitive to the disiplinary saying she l had seen text messages from her work phone and branding her a thief which she is not. This information should not have been available to her. Is there any action we could take agains the company for breaching confidentiality and disciplinary procedures?