CGI Flutter Developer interview questions

1st round was technical then 2nd round they have given the assignment I had completed the assignment but they rejected by saying I have copied from somewhere. It was not programming test, instead creating a project with proper clean architecture. I have not copied just i followed structured from a example given in internet. I think instead of rejecting by saying I had copied they can ask question from that assignment and if I will not able to answer it then it was fine to rejection. It was just a waste of time they might be take people only by reference of any employees.