Can't update bank info, and no reply from Shopify for 10 days

[rubik7]

I am trying to update Payments info (Bank details) in Shopify. This is our previous bank account that worked fine previously. The system accepts the change, but then I receive an email saying that the bank account can't be validated, even though it's a valid account that we've used before. I had 2 'chats' with support staff and spent over 2 hours of my time trying to resolve this straightforward issue. The issue was supposedly escalated to the Finance team, but no one gets back to me, and we are in a limbo now for 10 days. It looks like Shopify Support just refuses to work on this ticket. Can anyone recommend how to resolve this? I hope someone from Shopify support sees this, as I don't know what else to do here.