Account Query

i have a contract with Vodacom, so i decided to take another contract for my two boys,i called vodacom and they gave me another contract fro R275 for two phones.so they were delivered and the debit order on the 28th may went through.so now im suprise my bill went to R808 From R663.so i called Vodacom and a rude lady name Nomvelo told me its activation fee and then she dropped the phone.i would like to find out why am i charged that more, as to me it doesnt make sense and no one explained the activation fee.