Cibil score damage by sbi banker

SBI credit card telecaller called to my friend, and asked to take a card. My friend replied that, he have already credit card. Then they said no problem take this also. He said I need minimum lakh limit card, my old card also same limit. They said this is nearly 5 lakhs. Then my friend took credit card from them, but it is 23000 limit only. Then he asked to them and they gave un satisfied answers and finally they merged his old sbi other card and this card and limit came to 1 lakh. And said that your credit card is closed. But he present want loan and fried loan from someone and cibil score decreased 860 to 620. Then he inquired about it and there is penalty from nearly 1 year. He called to customer care and they said that card already closed. He asked no due certificate. But they not responding. Hyderabad sbi bank manager noted this as customer lost his card and not informed to bank ( for their safe side pur pose). Now his good credit score is damaged. He will pay that penalties, but his good score damaged. What can he do now. How can take action on them in this situation. Please help him.