Yes. they won't reply if you send them an email from the address other than that you had registered with.
I also had the same issue. I firstly sent them an email from another address, but the rely they gave me was that they couldn't share any details of applicant to a third party.
Then I sent an email from the address I had registered with. The reply came within 24 hours.
But the BGC status only changed yesterday, so I think I have a good 2 weeks before I wonder what is happening.