So I too received this offer via paper mail. Registered made said purchases and statement closes today.
I had sent a PM to them asking when it would post and on a lengthy reply the message was you need to send us a copy of the offer with other documents to prove it's validity.
I will wait a few statements to see if they post if not I will probably call them.
Shouldn't they have a record as to who they sent the offer to and my registration???