No
In today's environment, I would not join without a clear approval. But if you are ok to take risk, just the postal delivery notification is enough and is the same risk as joining with a receipt.
Yes, amazon does allow that.
I'm in the same boat waiting for my receipt (almost 2 weeks), how can you check your status online without a receipt number?
You can search on icert portal by company. Feel free to IM me if you can't figure it.
One of our team members joined based on portal notice since the physical receipt apparently got lost.
Haha.. I think that makes sense. Anyways every case will get a receipt notice so I think it should not be a problem