Unfair sales strategy, robbing game

I went to carnival mall mtn on 16/07/2024,for payment tht was outstanding,on my arrival I made contact with sales lady ,she explained to me the new cellphone package tht they have, she sold me 2 honor 200lite,they come with 500 pick n pay each,mean I was going to get 1000 voucher, which even now still not received it,and she changed my package tht I used to receive every month,when I go to the store manager she is arrogant and every month they deducted from my account, can u please help.