Selling fibre under false pretenses

An agent of Real promotions made a cold call to our premises. He sold us fiber and 10G speed lines and data. We were immediately billed, prorata and backdated. This was in Sept 2015. By 1 October 2015 we were still have the same slow internet ( i have photos of speed tests) and no fiber. We contacted Real promotons to cancel all as they sold us something that does not exist. Emails and telephone discussions followed and a ref no: of ***8 was issued. We requested that 1. it should be cancelled 2. our old speed contract be re-instated as it was before 3. that we were credited for period invoiced. We were promised that it will be done. To date, the 10Gb etc was still active on 20.1.2016 and the services to our line has been disconnected because due to monies outstanding. In 4 months this could have been resolved as promised. We refuse to pay and wait for Telkom to do credit. On 21.1.2016 we cancelled this service to this line as nothing was done to our dilemma since 1 October. We have since emailed the necessary people again but with no response to date and we are ending with a bad credit record. How can Telkom sell something that they know does not exist?