Bin it. Honestly, trying to register a WhatsApp Business account with Meta's "support" is like shouting into a void - except the void charges you for the privilege. Total lost cause.
What worked for me? Grab that same number, throw it into a fresh business portfolio. But for the love of all that is holy, don't be that brand that blasts messages day one. Let customers message you first. Just reply. After a couple of months of playing it cool, you can slowly dip your toes into marketing messages. It's tedious, but it beats pulling your hair out over Meta's non-existent support.