Turkish Airlines Misled on Website for EcoFly Ticket

I purchased a round-trip ticket from Istanbul to Tivat for April 10th - 14th through Skyscanner, and Etstur appeared as the cheapest agency. On THY's website, it stated that the EcoFly fare includes 15 kg of checked baggage and 8 kg of cabin baggage, as shown in the screenshot I provided. Trusting this information, I selected EcoFly and completed the payment. However, today I noticed that it says 'only cabin baggage allowance.' I spoke with the representatives, and they said I could purchase extra baggage, but the cost is quite high. It's very surprising to see such misleading information on their site, face a different situation when buying the ticket, and receive no support when wanting to upgrade the flight. I am expecting a resolution regarding this issue.