Not putting the client first

I visited your benoni lakeside mall branch on Saturday, 27 July and purchased a Samsung Galaxy A50. I was not informed by anyone at the branch that the phone was also available on contract. This only came to my attention when I looked at the brochure later that day, which I picked up at the store on my way out. I contacted the Branch to ask whether I could swap the cash payment for the contract and they advised that it could not be done. I do not want to return the phone by rather have a refund of the cash amount in return for a contract. Had I been informed upfront of the various options available to me, I would have chosen the contract. I feel that I have been deliberately misled and directed towards an option that is less beneficial to me as the customer. This is very poor customer service and now cell c does not want to help me.