Bad service-Billed for services not received

Hello Peter, I really trust that you will assist me in resolving this issue. I ordered Fibre services from webafrica in January 2022. The installation was only done in April . They also activated my Fibre in April 2021, however there no router to connect to the internet. I only received the router in June 2021. I only started using the Fibre internet from 10 June 2021. I had noticed that I had been billed since April 2022 for the services I have not received. Now I am sitting with a bill of 3 months even though I had only used the internet for 20 days in june 2021, therefore I should be billed pro rata in June. The installation was for free. The only additional costs should be the delivery of the router which cost R249.00. When I query my bill I was told that there will be no credit as they had to pay their suppliers even though they didn't render the service to me. Please advise what to do