Vodacom airtime disappeared - no action from them

On Sunday 3 September more than R400 airtime disappeared from my Vodacom account. I wanted to make a call and iso more than R400 airtime the balance was R0. I went to two of their branches, send emails to the Vodacom addresses, spoke to two ladies at their contact centre and tried their artificial 'not so intelligent' bod and to date I had nobody fixing this or even came up with an idea on how they are going to do this. Zero - nothing!!!! It is totally unacceptable that this can just happen and they do absolutely nothing to fix this.