False promotional items at Samsung.

I took a contract phone at MTN on the 7th of March 2021, The phone is Samsung Galaxy s21 256GB 5G.I was told at MTN there is promotional gift I must claim via Samsung. I did that on the 8th and I received an order number reference ***T4ZA, after a week I phoned Samsung one of the consultant told me the promotion has been closed on 28 of February 2021,but the magazine at MTN store says that the closing date was 13th of March 2021. I feel like I have been ****** by Samsung. This is the reference number from the consultant at Samsung ***.pls assist.