MoolChand Hospital — billing issue

My father has an angiography done on 19th feb'20. The doctor told that everything is included in package of rs 20000. But during discharge they asked for 3500 more. When i checked the bill that 3500 is of needles, gloves, patients suit, ecg etc.. We get this verified with doctor he said that billing team has added this wrongly as everything is included in package.
We approached billing head mr. Pradeep he said yes it is added wrongly and asked for 1day to get it reviewed. Now he is not picking the phone. Disgusting support from mr. Pradeep
We approached. Md prerna she said that pradeep will get this checked and now he is not picking the phone at all and not replying on whatsapp even after reading the messages.