On the assumption that your investment is in an EB-5 Regional Center project and in a loan model, the offering documents such as the PPM may state you will receive the investment funds back if the Conditional Permanent Residency is denied.
Since the EB-5 Immigrant Investor Program has an "at risk" requirement, there is no guarantee that you can regain your EB-5 investment if your green card is denied. It differs on a case to case basis.