Double charged for a device which is not in my possession

Good day I recently was contacted by their sales person who offered me a router and 10g(which is 5 day and 5 night)for 159 ,since I was working from home requested additional data of 10g and adviced it will be 214 monthly which I confirmed the total i will be paying monthly for the router and data over and over again to be sure.

To my surprise they delivered 2 routers with 2 different simcards and immediately phoned the call centre indeed the courier come to collect the next day 23 of January 2023.

I have been double charged and incorrectly billed in February and received another invoice which it looks like I will be double charged again...I have made numerous of calls to them since January and no action has been taken ...I keep on calling but calls get cut off and no one is bothering to assist....mind you I have been a client for more than 10 years and never missed a payment...

This is really frustrating as we all see the state of our economy and every cent counts..

I don't know what to do anymore...I mean can it take more than 2 much to resolve such a simple thing while all the information they need is there.