Unable to cancel contract.

I app**** for a Huawei p40 online and was called back well over two weeks ago and was promised to receive the handset this week, however even though I've set my billing date for the the 25th I was billed today and as a result incurred fees, I called numerous times even after going in to the Telkom store to get assistance was unable to cancel my contract, this frustratred me as I am not getting any assistance whatsoever and I haven't even received the device as yet.