Usually what I observed and read as well in this thread, when 2 parallel requests are put then only one goes through and other doesn't.
So thats why do it one by one. Let one DC get generated and then apply for next.
I also applied for signature and platinum together.. so only signature request went through as that was the first one I applied but platinum didn't get through.
So if other card is not generated in your case then apply again but after generation of first card.
Hope this will help.