Faulty Router

I purchased a router on contract from Vodacom on the 7/6/2015. When i got home it didn't work, didn't connect at all.Sent it back the following week and was replaced with a new one on the 18/6/2015. Connected it just before 18:00 and tried to download an fnb and a vodacom app till this day both apps didn't download. Downloaded about 4 games and 2 newspaper articles on one of our phones and 2 books on the pc. We basically used the router for 4 days (after hours on Thu/Fri) then used it for about half an hour on Sat and Sun. I've received an sms stating that i owe R6679.93 then i called Vodacom to inquire abt the sms, was then told the amount is now R9000 odd. This amount is ridiculous. There's no way we could use more than 100GB in four days. I've requested a detailled printout from Vodacom more than 4hrs ago. Kindly investigate this exorbitant bill for me.