Deceiving Offer

I have been with T-Mobile for over 10 years, and I have 7 lines on my account now. During the month of December 2023 there was an offer of FREE Galaxy S23 ultra on my T-Mobile. I decided to redeem the offer since I have been using my Galaxy S10+ for a while. After completing the required information, the price went from $0.00 to $25.00 /month or $ full price $799.99. If you know it's not free, why advertise it as free to get my hopes high and thinking T-Mobile has my best interest at heart. I have called customer service several times with no better response. Is that how you treat your loyal customers?