Bad service

I would like to make people aware of the bad service Blue Label Connect and their agents give to their customers, my mother took out a cellphone contract and she was not happy with it so she returned it and they told her to give them so they can check the device if it's still intact or not used, the checks were done and now they have to refund her they give her different dates and the agents keeps hanging up when we call, some just go mute and not respond when we talk to them. Can we please get assistance on this matter it's been 2 to3 months now.