I have WhatsApp on my Android phone. I changed from number A to number B and did not notify contacts. Later, some contacts told me that they had sent me messages on WhatsApp to phone number A, and I did not receive them. They see the messages as having only one tick, which means that they are on WhatsApp's servers. I would like to recover those pending messages, especially from the other contacts who didn't tell me that they had sent messages.
I changed the number on the WhatsApp app back to number A, but still, those messages do not appear on the phone.
Does the encryption key change when I change numbers? If so, those messages are indecipherable, even if the WhatsApp server does send them.
If not, has anyone managed to recover pending messages?
Note: this question is different from Will I receive pending messages after I reactivate my account on new phone? because the action is reversible (I can change phone numbers) and I know that the top answer does not work (I have pending messages that I did not receive).