Incomplete order that now requires a return instead of Makro completing the order.

I placed an order on 1 January 2025 to only receive half of my order on 16 January 2025. Now they want me to return the item that I did received because they don't have a way to log in complete orders and my order now shows as delivered. These are baby safety gate extensions so not anything out of the ordinary and I simply ordered two extensions. The process is ridiculous