Afaik the only back up you could have for Google Auth/Authy in Paxful is the QR code. Not sure as well if there's a proper procedure to report this, but try contacting their support via the live chat on the website. If I remember correctly that's what they suggested on twitter recently to the user with 2FA SMS problem, though it was SMS, it's still about 2FA.
I managed to get my account back. For those who are facing the same problem, just contact them the support from email and explain the situation, you'll be asked some questions that only the owner of the account would know (last transaction amount, payment method used) etc.
