Didnot deduct tds while buying for property from nri

We had purchased a property from a NRI in July 2017. However due to our ignorance we didn’t deduct any TDS from the sale price. When we realised this now and contacted the seller, he said he had made a loss on this property and hence we don’t need to pay the TDS. He also sent us a form 15CB which declares the same(but cannot be used by us). What is the best step to go forward with in this case? Thanks in advance