I'd like to see their Scriptural basis for this. There were 12 Apostles of Jesus. One betrayed him and was replaced (#13). St. Paul is considered an honorary 14th Apostle as he never was acquainted with Jesus in the flesh. There are no more Apostles, male or female. Zero, zip, nada. Where are they getting this?
We already know that women were prominent in the ministry of Jesus. Joanna, Mary Magdalene and other wealthy women were the patronesses of Jesus. We know there were many prominent female disciples and patronesses, but I have never seen anything anywhere naming them as Apostles.
Respectfully, we also know that Mary Magdalen was the first witnesses to the Resurrection, after every man in Christ's company until his arrest, abandoned him.