telkom is a joke

So I had a line installed on the 28 Nov.15. That line has not worked. I logged a call they came out on the 11 Dec 15. It works for one day . I logged another call. No response. I had to log another one cause I had received a invoice to pay for Dec. When this service has not been working. I speak to telkom they tell me I must pay it then they will credit me . How do u pay for something that is not working! ! Worst telecommunications company