Billed for package where there are no services

Yet again a request to cancel my contract has not been honoured. 3 months ago I app**** for an MTN LTE SIM card which I haven't used as it couldn't connect. The first month was paid for but still no service however, the second month I spoke to one of the guys advising them of the problem I had and either told them to cancel this package or give me another package of the same value as I will not be paying for another month where I am not even using the benefit. The consultant promised to call me back which never happened or when they do get hold of me, I'm in no position to speak and they say they will call me back. Now we were half through the month and still no call or the matter being sorted out then again I had to send through another email. And this time around, a lady from the cancellation department contacted me and said she had put in the request. But I see yet another month has come and I'm billed for services which were not used and of which I requested a cancellation or change of package. I cannot stress enough my frustrations when it comes to this because it's been 2 months dealing with this and getting no resolution. I haven't paid my monthly bill as yet as I wanted this issue to be resolved and now my subscription will be suspended and I need this sorted asap. And that's another issue that's gonna be a problem. Can someone sort this out please.