Cancellation of contract made impossible due to vodacoms ********* business practices

I have tried numerous times on different days to cancel my data contract. Yesterday an operator at the complaints section transferred my call to the cancellations number. After 34 minutes nobody answered the phone. I receive a message that I will receive a sms confirming the cancellation of the contract, but either do not get the sms, got one sms indicating that the contract is not eligible for cancellation while the in-branch staff confirmed the contract ends on 31 August. Sometimes when I try to connect to the cancellation number I am asked to type the number and then get a voice message that the number is invalid. It is clear ghat vodacom is abusing every type of tactic to prevent the termination of my contract.