Where's the CEO?

Can anyone out there help? For two years, since I cancelled my service, Vox has been bullying, hassling and threatening me for the return of a R600 item that I returned to them at the beginning of 2017. I have a waybill signed when the item was returned. That has not been followed up. This is appalling 'service' - consider that Vox employees and their contractors have been emailing and phoning me on NUMEROUS occasions; far more costly than just doing their jobs in the first place! I would like to make contact with the CEO, if they have any such person!