Vodacom ****ming client's into EasytoOwn contracts without full disclosure

My mom took out a EasytoOwn device with Vodacom at their store in the Garden Route Mall in George Western Cape, the sales person did not explain to her that in order to use this device she has to have data at all times and now my mom wants to cancel and give back the device and they are telling her she cannot. She has not had this device for even 30 days, she's had multiple issues and the non disclosed information was the last straw for her and she wants to cancel the rent to to own agreement. Vodacom has not been co-operative and their staff is tricking clients and not telling the client's everything especially something as important as this and all they care about is making the sale! I am highly disappointed in Vodacom, they need to rectify this ASAP and take back their device before we take further steps like involving the OMBUD!