No one can do anything except the IRS, and they aren't taking phone calls. It is important to remember that the advance payment does not change the total credit, only when it is paid. If you don't get the correct advance payments, you will get the rest of the credit added to your tax refund.
You can go to your IRS online account, it may allow you to view the credit payments and adjust your banking information. The IRS stated that taxpayers would be allowed to update dependent information but they still haven't turned that function on as far as I know.
https://www.irs.gov/payments/view-your-tax-account
Your husband should also check his online account, you have separate accounts even if you file jointly.
It sounds like you did not file jointly? Did you file separately for strategic reasons, or are you separated? If a person gets advanced payments but does not claim the child as a dependent on their tax return, they will have to pay the money back.
