[srrr]

While thinking about it I found an interesting fact: If they don't produce the data that lead to the account ban because they they "don't have it", they don't actually have proof of fraud anymore. If they don't have proof of fraud you can invoke GDPR article 16 "Right to rectification" and "unfraud" your account. Theoretically they can't argue against it because they don't have any data to argue with...

If they don't unfraud you AND don't produce the data they are not in compliance of either article 15 or article 16 and have delivered the proof noncompliance themselves.