It sounds like a legal question, a financial question, and an ethical question all in one. For a practical solution to your quandary, I see a few variables.
1. Whether or not the the investor is a licensed or unlicensed agent/broker,
2. The prices and relevant inventory (what you need, the market value, the wholesale value, and how quickly could your home be sold at each level),
3. Your time frame needed to sell
4. What steps you are willing or able to take to optimize your situation.
I would strongly recommend having someone act on your behalf asap with the advice of a real estate professional. I would be willing to give you an insider's perspective & evaluate your situation with no obligation on your part.
Texas Home Group, Realtors