I am seller, buyer says get off property

I am holder of private land contract. My house had storm damage done to it buyers insurance company sent her the check in both names. buyer got mad because we want check to go into joint account for repairs. buyer wants us to sign check over to her. We did this once she did not fix damages to the house.buyer says she does not want to talk to us and to stay off her property. in the mean time our house is having more damage done to it as she said it was leaking rain inside the house. how can we get her to use the insurance money to fix the house? the contract says she must maintane the house and all buildings. the contract says insurance money is to go to us first as sellers. I talked to the insurance company they said it was our problem, they could not even talk to us. what can i do with someone so unreasonable, she is telling her lawyer we are refusing to sign the check. am i trespassing if i go on the property to fix damages. I am worried about my house. she has had the check for over three weeks and the damage is going on with the house as this is the rainy season. she is doing nothing to fix the house.