Converted To Prepaid from TopUp

Good day,

On converting from TopUp to Prepaid, I was told that I would not lose my airtime which was 700 airtime as it is airtime and not minutes. I had been paying month to month. On day (1st April 2017) of conversion the airtime was no longer available. I spent over 2 hours on the phone to Vodacom and was sent from pillar to post to find out what has happened. To my complete disatisfaction, Vodacom has debited my account on the 3rd April for the TopUp account. No airtime was allocated. On understanding Terms & Conditions.. TopUp is a debit at the begining of the month and then airtime is allocated. When trying to get an answer from Vodacom, I again have been told they would send an invoice. I have reference number which was logged this morning, there is still no explaination or invoice. I was then told I must go to the shop to where I took out the contract. This is not acceptable. I would like that Vodacom contacts me and please explain what is going on. To date, still no reply....