New Contract messed up from day one!

i started a new vodacom contract on the 30th and the 31st it was activated. my problem is that i'm being charged for the full month of December and am now sitting with way too much airtime to use. the contract is for work purposes and I cannot claim for usage as there is simply too much airtime. the consultant at vodacom Jan/Abraham stated that it should not be a full months fee and airtime but a pro rata fee that i need to pay, which i am ok with. he contacted the call centre who said that the money wont come off at the end of the month but during the month and then again at the end of the month. this doesnt help me at all. this is not what i signed up for please rectify this! remove the R200 airtime that i dont need and didnt agree to. if this is how the contract starts then how enjoyable will my experience with Vodacom be? also my current bill shows itemised billing and caller line identity as a double debit for the end of jan and vodacom told me there is nothing they can do about it. this service is as bad if not worse than cellc and that is saying alot since they are the worst service provider out there. did not expect this from an international company like vodacom.