I don't know about Peacock specifically, but the fine print on many of these introductory special offers state they are for new users only. Have you had a previous Peacock subscription?
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I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
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Ultra 4800 | Streaming Stick 4K+ 3821 | TCL Roku TV 43S245/C107X