As a bit of a sidebar, I'm concerned for you good folks. One of the indexes you posted appears to have "CardNumber" as a clear text value. I hope I'm misreading that. PCI specs and most specs on PII say that such things must be encrypted.
Could you attach a copy of what the Clustered Indexes look like (I see you posted 1 already but a single attachment would be convenient) and all the Non Clustered Indexes for the two tables in question? It'll help with analysis.
--Jeff Moden
Change is inevitable... Change for the better is not.