vodacom ****med my mother

There was a promotion at vodacom for wifi routers. My mother got one for me then after a week they sent a package after my mother signed for it she realised that it's another router and when she calls vodacom they just told her she shouldn't have signed the package and refuse to take it back but how couldn't she refused to sign it if she didn't know what was in the package. Now my mother is paying for two routers whereas the other one is not working and the sim card is still sealed.and now it all looks like the service provider wanted to sell so many things that he/she end up taking advantage.