Can't Send From Desired Email Address

[L13158]

I want to send an email out for our other business. I tried to verify their email address to add it to the list of approved senders. Once I did that, it was never added to the list of senders I could choose from. I tried a second time & never got the verification email - I assume because it knew I had already done that. That was for the email with our custom domain. Then I tried to do it with the one for our free gmail account. Same thing. Then I found out about the new rule for February that it HAS to be from your own custom domain & authenticated through the back end of your site. I'm not able to do that right now because of a domain dispute. We own the domain through GoDaddy but have to prove that to Wix - have sent the required info & are not hearing back. Constant Contact said not to worry if you only have a free gmail account, because they'll automatically add a .ccsend extension to your email address. But I assume that's only if it was already in there before February 1st, which is today, so it seems we're out of luck. Appreciate any advice, because I can't reach customer service until next week.