Changing Vodacom Contract Number

Hello,

My girlfriend got a new contract with Vodacom about a week ago, Vodacom phoned her and confirmed the contract. We then get the device and the sim card and activated it. Now this is a new sim card so there's a new number linked to it. So we go in store to ask them to change the number from the new one to an existing Vodacom number. She then tells us that this is not possible because it should have been done before the contract went through, but the Vodacom sales team never even asked if she wanted to do a sim swap or port a different number. So how are we supposed to know that it cannot be done if none of the Vodacom reps spoke to her about it. I've had this number for years and I have everything linked to it. I must change everything because Vodacom wants to be difficult now. I've had a contract before and I've changed the number of that contract and no one said that we can't change it afterwards, so why now is Vodacom being difficult and we're not allowed to change it? This is not on Vodacom, we chose you to be our service provider but your customer service is below average.