Insurance that I didn't ask for

I have a router contract with cell c of R300 a month. March they call me to offer me router and I accepted the offer and it was a R300 per month, they insurance my router without asking me and I didn't know .by 16 March they debt R411 and I was surprised because I was expecting only prorata to be debited and I thought is prorata and my installment, my installment was on 7April 2021 but they debit on 16 March. I reported my issue no one called me until I called them after receiving my statement telling me a out R124 overdue and they said the is the insurance that I didn't ask for I cancelled that insurance but the R124 out standing is still the and I won6 pay it the rather cancel my contract of am expecting to pay R300 a month not over that pls help