Vodacom money seeking *****s

Good day I have done a upgrade on my rooter and got the new 399 unlimited data plan from vodacom. Firt when I cot the device it did not work. so I hade to go in to vodakom key west . There the lady told me I must do a s swap so I did after this se told me I must wait 1ouer for it to work . Bit stil it did nor work so I phoned vodacom and they told me that on there side every ting must work . if not I must sent the device back. so I did. now they told me because I sent it back tha I must wait til end of November to apply again for the contackt. the problem is that they sent me a bill of 399 for this month but the device did not work from day one . how can the treat they Costomer like that.