Issue with Erasmus Promotion Code and Baggage Allowance With Turkish Airlines

On January 25, 2024, I purchased a ticket from THY for a flight from Istanbul to Krakow. As an Erasmus student, I used the promotion code provided under the protocol agreement between the Turkish National Agency and THY. According to this promotion code, I am entitled to 40 kg of baggage allowance and a 15% discount. While purchasing my ticket, I received support from a THY customer representative via live chat. Instead of the 'Eco Fly' package, which does not offer any baggage allowance and is the cheapest option, I purchased the 'Economy Class - Extra Fly' package, which is approximately ₺1000 more expensive and includes 23 kg of baggage allowance. Therefore, my 23 kg baggage allowance was supposed to come from the 'Extra Fly' package, and the 40 kg baggage allowance from the promotion code, totaling 63 kg of baggage allowance. However, after the payment process, I noticed that I only had 40 kg of baggage allowance. If I was going to receive the same benefits regardless of whether I chose the 'Eco Fly' or 'Extra Fly' package, why didn't your customer representative inform me, or why didn't the system provide a warning about this? I cannot see the total baggage allowance before completing the purchase. If I had known, I would not have paid an extra ₺1000 for this package and would have chosen the 'Eco Fly' package. I request that my 'Economy Class - Extra Fly' package be changed to the 'Economy Class - Eco Fly' package and the price difference be transferred to my IBAN, or that the 23 kg baggage allowance from the Extra Fly package be added to my ticket.