Vodacom upgrade

I took a contract phone in 2022 December, last year (2023) October someone from Vodacom called me and told me about Vodacom promotion. He told me Vodacom is gonna increase my package but I'm still going to pay same amount no changes. Only to find out in December 2023 that my package has changed. Now my bill is over 3000. I always make sure I pay 300 but I can't pay that 3000 Vodacom please fix this.