In my experience, it routinely takes several days for tix purchased at UA.com to post my CC account. (I have never purchased a ticket with a debit card).
In Nov 2004, I purchased a ticket for travel in Dec 2004, and the charge appeared as "pending" on my CC account for 4 months, three full months after I returned from Hawaii!
Bought a ticket Dec 21 that just posted to the account on 12/28.
These are anecdotes and one person's experience, but what you're describing seems like par for the course for UA.com (although you don't explicitly state the date you purchased the ticket).