I don't see how to delete this post, but I found this on another post. I followed the instructions, the phone was answered immediately and the cancellation processed.
"I was able to get through right away by calling 1 800 772 4642, stating “Avios Booking” when prompted to say what I’m calling about, then enter in my Avios number when prompted, followed by my passport number when asked to enter ID information. Then say yes to confirm you want to talk to a representative. I was connected with an agent immediately, gave my last name and record locator, and cancelled on the spot. Refund should "process" in 72-hours, and Avios returned in 5 biz days."