Vodacom Canal Walk is the worst

In October 2023 i received a SMS that my contract is ready for a upgrade. On 7 November I went to the Gape Gate Vodacom branch to find out about the upgrade and the lady said I can upgrade but there is still two installments left. I was upset as the SMS said I can upgrade now but said I'll wait a month and left. Just before the end of November I went to Vodacom Canal Walk to find out the deals because I want to upgrade after the debit order because then only one installment will be left. The guy said I can upgrade now with one installment left because my debit order is going off before the new contract goes through, I asked him a few times are you sure, he said yes. November my account was debited, December my account was debited. To my shock the invoice for January also included the installment for the previous contract. Contacted the store and spoke to the manager. He said sorry he can't do anything because I signed. I said but his sales person assured me there is only one installment left and that I already paid two, he said he will investigate and come back to me, never did, that whole store in Canal Walk that I worked with is ***********.