Decathlon Wrong Size Jacket! No Cancellation or Exchange Option

Around 11:00 PM on October 6th, I ordered a Wedze children's jacket from the Decathlon online store. I mistakenly selected the 5-6 year old size when ordering, but then immediately wanted to exchange it for the correct size, the 12-13 year old. However, I couldn't find the option to change the size in the system, and there was no option to cancel the order. Furthermore, the call center and customer service were closed after 6:30 PM, so I couldn't reach anyone. My order number is TR3828235584. I paid ₺1,670 for the product. I understand Decathlon has a 60-day return policy, but the lack of an order cancellation option and the inability to reach customer service have been frustrating. I request that the correct size be sent, or if that's not possible, my order be canceled.