Former Employer keeps sending text messages accusing employees who have left of "poaching"

A former employer is accusing myself and other former employees of poaching their staff. However, in all cases the staff have come to us for new jobs. Through out this situation they sent me text messages, and emailed the owner of my new company telling them they thought I was poaching their staff. Another manager has been gone for months but continues to receive text messages accusing her of poaching and belittling her new employer. In no cases has myself or this other manager reached out to employees first, we have only assisted employees who have reached out to us in finding the right place to apply should they wish and answering questions about our new locations. Can the employer be sued for harassment?