Modem not active

On the 27th of March I purchased a laptop contract at the Vodaworld branch. Upon reaching home I tried to activate the sim and I realized this message on the phone: Sim card registration failed.On the 28th I called Vodacom which indicated that the store hasn't done the activation. I called the store, and Polelo(staff at the store) said she will do the activation and call me back. she did not return my call on Saturday.On sunday the 29th I called Vodacom to try the activation and was not successful, then called the store and was again assisted by Polelo who indicated that the sim is not active I asked her the reasons of not providing feedback but could not get an answer. I spent the entire day calling vodacom and incredible connections vodaworld to get the matter sorted and could not get help. Today Tuesday the 31st 4 days later my modem is still not working and there is no way forward. The number allocated to me is a number that was once de-registered and has since been inactive, I'm disappointed by the service and the fact that I have to be the one who spends my time and money doing the follow up. why sell a product that cannot be used.