Guide published our project paper without acknowledging us

Hey everyone, I don't have any idea which sub to post this to. I’m a 2024 BE graduate. My project group recently found out that our guide published our project paper under his and other faculty members' names without informing us or including our names. During college, our guide insisted on an expensive journal (₹30-40k), rejected our affordable options, and told us to publish later after graduation. All of us group members are now in different places for further studies or jobs, making it harder to address this collectively. We’ve tried reaching out to the guide but haven’t received any response also there’s currently no HOD appointed for our department ( don't know why) to address this issue. What steps can we take to ensure proper acknowledgment for our contributions? Any advice would be greatly appreciated. Thanks!