2 months notice to cancel

I sent an email to your cancellation department on the 03/02/2015 to request that my contract be converted to pre-pay on the 24/03/2015 at the end of its contract. I received an email to confirm that I would need to send my request after the contract expires in order to keep my number on pre-paid. I was advised that I don't have to provide a months notice .I then called your call centre to confirm when will be my last months subscription as I don't want to pay after the contract expires. The consultant informed me that I will still pay for the month of April 2015 as I will be receiving my airtime on the 21/03/2015, hence the reason I will pay at the end of April. Today I find out that if I convert the number to pre-paid I will lose the airtime as well as the data but still have to pay at the end of April 2015. What do you take me for are you telling me now that I basically need to give you 2 months' notice just to convert my number to pre-paid and then I still lose out on data and you going to make me pay in full at the end of April. I am disgusted at the service received from your call centre. Please sort this out and get back to me.Reference Numbers:*** and ***, ***