If it says, your account is associated with another account, you or someone has already an account verified by your number. Use a different phone number or try to figure out and log in to the existed account.
I don't know what else to do, but for whatever reason, no matter the device, browser, or even clearing cookies and what not, does the button work when it asks for the phone number to send a code. I'm not sure if it's the last step, or if I'm overlooking something, but when I press the button, nothing happens.
Thank you for reaching out to us, Michael.
I've escalated your account information to our support team. One of our agents will reach out to you directly to assist you with your phone verification process.