Found it. Here is the key detail:

"They're supposedly going to send us a cashier's check in like two weeks for all the money that was in our church bank account but in the meantime they just took all our money away," Anderson said.

So, before BOA or any other bank closes an account, they will send an overnight letter to the client via UPS or Fed Ex so that there is a written record. The client typically has 30 days to close their accounts on their own, and move funds to another bank or credit union.

If they neglect to do so, at the 30 day mark, the accounts are frozen, and the bank then issues the client a certified check. It can take up to 2 weeks, but typically happens faster than that.

So what this tells you is that in all likelihood, the secretary got the UPS package with the letter, and threw it in the trash or set it aside not realizing what it was. Or, it is possible it got sent to the wrong address, though that is rare. Banks don't close accounts out of the blue without having given the 30 days notice - for liability reasons alone this doesn't happen.

As to rationale, we will never know the bank's reasoning. The bank never discloses why they would do so. But think about it - What kind of organization misses a Fed Ex or UPS envelope from their bank and then disregards it? I guess mistakes happen, but it tells you a clue about how the client runs their organization.