Billing Refund

I sent an email cancelling my landline back in April 2017, After numerous calls and complaints including on Hello Peter, it was only cancelled in August 2017. For all those months I was forced to keep paying for a service I didn't need, and now Telkom won't do the simple thing of refunding the money I spent. Why does a company have to be so inefficient? Can something be done about this

Really frustrated