Wesbank refund process is poor

My account was paid up with Wesbank in July 2019 . In November 2019 an amount was paid into my Wesbank account by mistake. More than a month later I have not received my refund and the service I have received from the Wesbank agents is poor. I have spoken to more than 10 agents and each time I get sent from pillar to post and they never respond to emails. I am so frustrated because I don't know who to complain to.