Salesforce Backend Engineer Intern interview questions

I was given a home assignment, it had 2 questions one was medium difficulty and one a bit harder later I was contacted via an HR coordinator for the program and did a phone interview, it was longer than anticipated and it seemed to be a good one, and at the end she told that a hiring manager from one of the groups will be in contact with me, but that didn't happen regardless of my tries to reach out. and months after I received the rejection letter without ay explanation.