The I-526 approval will remain valid, and you can make another attempt at obtaining conditional permanent residency through the U.S. Consulate. Refunds will depend on the Regional Center into which you invest, so it is very important to retain U.S. immigration counsel to review all documentation for immigration risks and consequences.
The refund of the capital invested are governed by the terms of the regional center project. It is vital to consult an attorney to reduce any immigration risk a regional center project may represent.
Your investment principal can be returned to you if your conditional permanent residency is denied. You need to make sure this stipulation is covered by the security offering documents. However,after you have obtained your conditional permanent residency your investment principal has to be entirely at risk, and if the business fails you may lose the investment funds.