Ownership Rights: Land Contract and Vendor

My question involves personal property located in the State of Michigan.

I bought my property via a land contract from my sister and it was signed on June 3, 2016. After many attempts to get her to move her personal property from the 3 sheds on the property I sought advice from a local lawyer and sent my sister a letter outlining the legal aspects of the contract - many of which she was misinformed.

She has shown up today on the property (with my permission) to begin to remove the personal items. Trouble is, she's setting up a yard sale on my property to sell her things.

All day long she has been knocking on windows and walls using foul language to try to get me out there to help her. I probably would have if she had been polite about this situation.

Does setting up her things for a yard sale without my permission constitute trespassing?

Let me know if you need more info.

Thanks!

Rita

Ownership Rights: Land Contract and Vendor