Data contract

I've been trying to cancel my prepaid vodacoe data contract no one can help me. I have an uncapped data contract so having to pay for 2 data contract is useless. This morning I've recieved e-mail regarding one of the contract but I do not know wich one it is. So I asked if the can phone me back. I did recieve a caal but was bad connetion and they didnt phone me back I would like to cancel my prpaid data contract