Damelin appalling Customer Service

My son studied at Damelin in 2018. When I signed up I was given a debit order to sign which the account manager completed. I was advised that they would take 10 installments plus the upfront cash I had. Needless to say after the 10 installments my son completed the diploma in 2019 and could not get hes results due to outstanding fees. It has been a back and forth with rude people and being told they dont care what happens I just need to pay that money. Can someone please help sort this issue out urgently as right now Damelin is a zero on my list.