I have the exact same issue with my IB+ account. This has still not been resolved and it's been several months since OP started the thread. Amazing.

Funny thing is I had an old 8 digit account before. Iberia created a new account for me when I applied for their Icon credit card, even though I told them I already had an account and gave it to them during the application process! It took 3 months for them to transfer my old 8 digit account to the new 9 digit, and now I am facing this issue with the Amex transfer.