What to do

My father received a treatment from dentist which he is knowing from 2 years. They had a talk and the Dr agreed that he will perform Implant and will refund each and every money involved , as my father was knowing this man from quite a long time so he started the procedure as he knows after the implant he would get his money back. All the things where going properly but then at the time of refund he started making excuse , though he had written every thing in his prescription about the money spent and signed with seal also, but was repeatedly giving dates and also not completed the implant. But one day after so many requests he gave us a cheque of Rs 3 lakh and said to submit this in bank on the given date. Then suddenly on the date when we where about to submit the cheque he said pls don't put this as I would be giving you cash but he gave us 1.5 lakh after Insisting . So as he had already given 1.5 lakh but still he has to refund 2.20 lakh now also, the earlier cheque which he had given would have become obsolete right ?. And now also giving dates continuously what should I do pls suggest me as I'm in complete mess and wants someone's advice.