Block specific email provider

Hello everyone,

on our checkout page the customer only has to enter his email adress. To this email adress he gets his password sent and after successful payment, his download links. So currently we’ve a problem with outlook and t-online.de we can’t send emails to them. We’ve checked everything we are not blacklisted but outlook/hotmail/t-online.de don’t let us send emails to that addresses.
So my question now, is there some plugin that I can for example say that hotmail/outlook/t-online are blocked and when the customer trys to place an order with such an email, he gets a notification that he should another email provider?
Kind regards

exxis