Refusal to link my number to my new contract

My name is Puleng Elizabeth Kganyago . I took a cellphone contract with Vodacom last week and received my package yesterday the 1st February 2021. in the package there was a cellphone and a sim card. So I want Vodacom to link my current Vodacom number to my contract so that I do not change my number and receive airtime on my current contact number to my surprise Vodacom say my request is not possible but on my husband cellphone contract it was possible. I feel like the consultant I poke with was not on the mood to assist me, just wanted to get rid of me. Nothing is impossible. So my plea to Vodacom is that please help link my current contact number to the contract I took with you.