Unable to verify identity

when I get to the part where I have to enter my date of birth to confirm my identity I get an error message that says "unable to verify" and am re-directed to the assistance chatbot that doesn't have a prompt that covers identify verification issues. I tried calling the assistance phone number but I get stuck in circles because I don't have an existing plan with Xfinity--because I can't verify my birthday to get a plan. I have tried on two different browsers, cleared my cache, and triple-checked that I am entering my correct birthday in MM/DD/YYYY format. I have no idea where to move forward from here and would greatly appreciate assistance I’m just trying to finance on my new device