I submitted the project in 2 weeks after the initial interview. Then 5 days later they came back to me with feedback says this is not a N way cache. I was honestly unsatisfied with the feedback as I did a lot of research, had a read of multiple open source projects and even draw the UML and Cache diagram. After emailing the hiring manager, he came back with me not using SOLID principle and other design issue. That's not convincing and I'm confident with the project. I'm not even sure if they had a read through the solution. Anyways, I am happy to face the failure but the feedback doesn't really help.