The only right you have is to return a product that does not do the job it was sold to do - it is not fit for purpose. If you were sold the cards and can prove you were told they would work fine with the Soundblaster card then yes you can return them. But I very much doubt that is the case.
Depending on who you bought them from you may be able to return them as a good will gesture on behalf of the supplier but you do not have the right to do so.
There is nothing wrong with the product as a single item so you have to accept that they don't meet your needs and perhaps more research would've shown this.
Sell them on, count your losses and try again.