iMessage, FaceTime, Apple Pay stopped working

After using iMessage for years and Apple Pay for months, and after updating to iOS 13.x iMessage stopped working. I tried the self help steps of turning iMessage & FaceTime off and restarting and trying again. All this accomplished was deleting my credit cards from Wallet. I didn't try resetting network settings. I didn't want to lose my WiFi passwords. None of these steps allowed iMessage to activate or Wallet ADD to work.

I was escalated to two different AppleCare Senior Advisors. The first one had me install the Baseband logging profile on and reproduce. Then a week went by with no updates. Second advisor said the data from the first time wasn’t uploaded and had me do it again. He suggested that I reset all settings. I declined. He said he could do nothing more for me but would keep the case open in case Apple engineering addressed it. I retried the self help steps of turning off iMessage & FaceTime and restarting, with no luck. Then I noticed that iOS 13.3.1 was pending install. After the the iOS 13.3.1 update I signed in to iCloud via Wallet and Apple Pay began working. After that I discovered that both iMessage and FaceTime had activated. iMessage was working again.

The advisor was unable to explain why iMessage stopped working in the first place or which steps I or Apple took to get it working again.