typical vodacom

On 16 April 2015 I did a upgrade on one of my contracts with vodacom ***) I received the new phone a day or two later. When I did the upgrade I was informed that I would be on a different contract as of 1 May 2015. The new contract entailed that I would be receiving a certain amount of airtime each month and when that runs out I would be able to recharge as pre paid. Yesterday I tried to recharge as my airtime was finished. I can't. I phoned customer care and according to them I will only go on the new contract from June. Now I'm stuck with a phone I can't use.