Harrassing, intimidating and utterly ***********!

I would like to give this company minus stars! I have received threatening emails weekly for about a year for an amount they claim is outstanding from Vodacom. I have always had MTN accounts other than a one year Vodacom account about 10 years ago which was cancelled and cleared at the time. With every mail I receive from Hammond Pole I ask them to send proof of what is owing. I have never had a response from them. I eventually contacted Vodacom who have no record of me owing anything to them. This is harassment and I wish I know who to report them to for this unprofessional and intimidating behaviour.