We do not generally block projects because of *incoming* DDoS attacks. If a project receives an abuse notice, it means that project is *causing* abuse somehow, whether known to the owners or not.
Please note that unfortunately we cannot discuss the details of any particular customer's account on this public forum, which means that the likely outcome here will only be speculation about what's happening. Unless the customer chooses to share the outcome, which is entirely up to them.
Sorry we can't be more specific about this exact case, but rest assured the customer is in contact with our support teams.