Lufthansa Customer Service Ignored Lost Luggage Complaint

During my flight on March 18, 2023, from Bodrum to Brussels with a layover in Berlin via Lufthansa Airlines, I unfortunately experienced the inconvenience of my luggage going missing. Although two of the bags were delivered successfully, one bag is still missing. It's been almost 5 months without any acknowledgment or reply to my inquiries. I'm contemplating pursuing legal recourse. I think Lufthansa Airlines has not taken this matter seriously enough.