I had a Chase Slate that I cancelled the same day I was approved for it. It showed up on my credit about a month later. It did not mess with my score at all. If you have any "manual reviews" you may need to explain it, but that's about it. 
The card application gave you one or more credit inquiries, and the card itself lowered your average age of accounts. Beyond that, nothing really. If a future lender demands an explanation, just tell them you changed your mind about the card at the time.
@HeilFico wrote:I had a Chase Slate that I cancelled the same day I was approved for it. It showed up on my credit about a month later. It did not mess with my score at all. If you have any "manual reviews" you may need to explain it, but that's about it.
Call Chase and see if they're willing to take it off your CR.
From what I've read, they seem to be willing to delete the new account from your CR, but not the inquiry. So at least you don't take an unncessary hit to your AAoA.
@Princess86 wrote:Hi all,
I signed up for a MC with US Airways inflight and called afterwards to try to cancel the application. Fast forward 2 months they sent me a card anyways and I closed the account before using the card. How will this affect my credit and for how long? Is there any way for me to call the credit bureau and tell them the situation so that it doesn't affect my credit?
Thanks
It will not affect your credit much. All it did was to report a new account, which lowered your average age of accounts, and you took 1 inquiry for it.
You can try calling Barclays to see if they're willing to delete it off your CR. If they say no, no harm done regardless.