MTN complaint: service and charges

I took out MTN data contract for 2 yrs. I was given a router and sim. The router was forever red and within 7 days I returned it and was requested the box which I lost. I understood when told that they can’t help without the box. I was never given an option, I had to go back again only to be advised to bring the router so it can be sent for repairs- I still don’t know why I was not advised immediately after I told them that I lost the box. The router returned because it was broken. I then came back after 5 moths to ask what to do as I was always debited with monthly premiums of somthng that I was not using. I was then advised to buy a new router. I bought a new router and it was still doing the same thing. I went back and was advised to buy MTN router not any other router, because I spent a lot on routers, I then bought a new one from MTN on the 23082022. I went home and inserted the sim card only to find the same old problem persisting. I took it back on the 25th . I was advised to bring the box along the next day which I did. Only when I brought everything back did one staff lady decide we should test the sim card and upon realizing the sim card was the one with problem she advised me to do a sim swap and I asked how much is gonna cost me and was told R150. I wanted to be sure if it was going to work and she advised me to buy sim of R10 plus R50 data which I did and found out that it is working. I went to do sim swap on Mon 29.
My issue is that I have being paying premiums every month and my contract is only left with 6 months. I paid for almost everything to get it work. MTN gave me defective sim from the onset and I have to pay all these monies that I have mentioned, plus they have being taking monthly premiums without worrying whether it was in use or not. I feel they should have contacted me before I contacted them- the fact of the matter is that I have never received the service I paid for and MTN did not care, as long as they could get my money. I want you to put yourself in my shoes. I want you to do what is right and just. I have being taken forgranted and I want this to be corrected. Justice be served.