Virgin Atlantic and Delta Air poor service

My son lost All his luggage at Heathrow. We booked a flight using Delta Air and it was confirmed on Monday 08 August 2022,we get to the Airport on 09 August 2022 to pay,there is no office administrators at Delta Air to assist us,we then had to pay almost R40k for a one way flight from Jhb to Atlanta,the booked flight was R23k.

My son had to start school on 11 August 2022 at Morehouse College in debt(the additional flight fees) without any clothes and essentials,leaving my son stranded.To date no feedback on his luggage and saw his luggage at Heathrow on the outside platform,while he was boarding his flight.

Please,can we get his complaint for a refund and his luggage returned soonest?