Unauthorized debit orders

Middle last year my son purchased the rain router online, only to find out the signal does not pick up where he stays in Rustenburg! The agreement is you only pay if u use it! He never used it as he couldn't. He never had any issues until a few months ago when they just deducted Over R600 from his account! He phoned them, and the person said, yes he can see its a mistake a he is not using the Rain data! And that they will refund him! He has still not been refunded even after many attempts of calling them! Today 26January they deducted again over R700 from his account! We have been calling them none stop but no answer from accounts departments and sales will not assist!