Cell C Fibre - Terrible service

We app**** for a fibre line at the end of Mrach, just before we moved into our new home in April. We app**** over the phone so the sales agent filled in the application form, and of course the calls are recorded. We took the promotion that they were running at that stage for 3 months free, as well as a free router and a free Cell C Black Box. We received the free router and the free black box, but noticed that they have been debiting our account every month for the last 3 months, so we did not get the 3 months free. I have been trying to sort this out for weeks now with their support people on the phone. Last Wednesday an agent phoned me and told me that the option for the promotion was not ticked on the application!!! We did not fill in an application. I told her that they would need to go and listen to the recordings, she agreed. I phoned today only to be told that the issue had been closed!!!! The agent today re opened the case but I have been waiting for weeks and honestly feel like I am getting nowhere with them! Our sales agent also said that we should have gotten the free 3 months, and he said that he would escalate from his side. It is frustrating as there is no actual office to go and see anyone about this and they just keep giving me the runaround.