British Airways - Boarding denied in flight

Our Family Was Unexpectedly Denied Boarding At The Last Minute By British Airways Staff Because Our * Year Old Child, Who Holds An Irish Residence Permit, Was Missing A Visa Not Required For Entry To Ireland. Both Parents Hold Valid Irish Residence Permit. Ireland Authorities Do Not Require Visa For A Child Under ** If Accompanied By Parents. Britisdh Airways Staff's Lack Of Knowledge About Ireland's Visa Requirements For Children Led To A Wasted Trip, Significant Stress, And Financial Loss To Our Family. "British Airways" Error Caused Not Only Logistical And Financial Disruption But Also Significant Emotional Distress For Our Child, Making A Stressful Situation Even Worse. On Complaining The BA Portal, They Asked Us To Take Our Complaint To Travel Agent Who Would Raise Issue With The Airline. This Is Completely Weird. I Went To The Traval Agent As Well Which Is Makemytrip. They Are Not Able To Do Anything And Asking Us To Deal Directly With The Airline. I Would Request A Refund Fo The Flight Tickets As Well As Suitable Compensation For The Trouble Caused To Us.