That is really bad form of a company to substitue a lesser valued creature for a high end value. I would contact the company again and say that you do not want plain cherry shrimp as re-embursment, rather that you would prefer to wait until they have more rili shrimp available or they can refund you the funds owing. I am guessing that you would have paid quite a bit for your rili shrimp, I know they are not common in Australia and when they are available they can be up to $30 each especially for high grade rili's.
If/ when the two new cherry shrimp arrive, if possible I would not put them with the rili's you currently have, the standard red gene is the stronger gene (I suspect rili is more recessive) and breeding the normal to rili could potentially end up creating the bulk of normal cherry offspring with limited if at all rili offspring.
If possible I would let the three rili's you do have mature and see if you do have a mix of male and female and only once they are matured then see about maybe putting just one of the normals with the rili for a one off breeding. Then after the female has had her shrimplets remove the female (mainly if the female was the normal) and leave the shrimplets to mature with the rili's. As they grow any rili offspring that occur out of this breeding can be left with the original rili's while any normal looking cherry's can go back to the other normal cherry's.