New contract not activated

I had a Blackberry and my contract expired. I took out a new contract with an Iphone 6. The sales person read the new contract to me - how many minutes, sms, data etc I will have on the new phone and put all my old phone's information on my new phone. I asked him about whatsapp and he said 800megs should be fine for downloading all that I need to download and I went happily out of there. Last night I checked my billing and my account was more than R2000 and all for data been used. I went there today and the person that helped me was busy and another guy checked my account and said that it is correct and my new contract only starts on 1 February. Did no one think of telling me that the day I got the new phone??? Did they think that I would not use data or phone until the 1st of February?? No, they are just plain ****** and they deceived me because why when I asked how much data I would need for downloading stuff he assured me the 800 megs on my contract would be enough? He knew that I was going to download stuff and that day and NEVER EVER said that the new contract would only start 1 Feb. I want my money back for that data and an apology from Vodacom.