bad service

my mobile router and sim card was ****** in november 2020 as soon as it was ****** i phoned in and asked to blacklist device and stop the sim card, as well as submitting a request on the telkom app.i was told the sim card is blocked.i recieved my january statement and realised that the card had not been blocked as i was ensured it was,there was an amount of R600 spent on the sim card,i phoned in to ask what was going on and what can be done to be told by the opeartor that the sim card was not blocked but he can see i phoned in and logged a request,i further asked what can be done about the money that was spent as it was not negligence on my side,i was told unfortunately there is nothing i can do but pay the account,i feel this is unfair and is negligence from telkoms side.