Seller Tenant stay in home for 15 days after closing.

[Pooja Gupta]

We close a deal for a house on agreement that seller tenant can stay in house for 15 days after closing. We ask our agent and he told us we will be getting rent for 15 days. Now, the seller is not giving us rent for 15 days saying that he has asked tenant to stay for free for 15 days. We are at loss since we are paying for rent for current house and also mortgage and insurance and other charges of new house. Who has given authority to seller to do so. Please let me know what we can do in this case?