Blitz-Axxess Billing For Incomplete Installation

My fibre line was installed on Friday 10/05/2019 and I feel like the guys who installed it **** to me just so that they can get out of there. I am still unable to use the connection today (14/05/2019). When they were at my house they told me that I need to phone Axxess to advise them that the installation is complete and then the connection will be activated. When I called Axxess they told me that they get that information directly from Blitz when they sign off on the installation. Later that afternoon the connection was still not active. After numerous attempts to reach your technical department I finally spoke to someone who acted like he was doing me a huge favor by completing the order which as he said should be done be the admin staff. Connection still didn't work. I called Axxess and I was on the phone with a technician for over 40 minutes without the problem being resolved. The Axxess technician said that he has logged a ticket with Blitz about the problem. Last night when I got home I tested the connection and I still had no internet. I have since received an invoice from Axxess for a service I cannot use and their excuse why they cannot reverse this invoice (INV ********** ) is:

Unfortunately we unable to reverse the invoice, due to the provider Blitz signing off your order, they signed it off on the 13th May immediately once activated they start billing accordingly.

Regards, Shanee Govender

Please advise. I cannot be billed and pay for something that cannot be used. I will take this matter further if nothing is done about it.