SiPay (Turkey) interview questions

The interview process had went well, according to them at least. I managed to go to the final interview round and had feedback that it also went terrific, where I met the head of product in person. However after the last interview they sent me a non-standard case study, which they initially said there was no case study involved in this interview process. I was told that the case study was a bonus to see if I would also be used to function in the new product line. The case study was for a new product line and included in it were questions that were near impossible to know or answer in the span of the two days time frame they gave me. Given that they knew I was already working. Nonetheless I sent the case study using the best of my knowledge, research capabilities and the help of AI. I am extremely firm on the idea that even they dont know the answers for the questions on there. Anyway, they sent me a rejection message 2 months later, from an intern who recently joined. No communication was made to me regarding the reason for the rejection. I would like to say no thanks to the HR, Büşra Çelik for the way she handled the whole process. Even after I called and messaged her asking for an availability to discuss the reasons. She said yeah sure let me call you in a bit. She never called.