So according to the regulator Uber automatically suspended driver accounts that were flagged in decision of fraud or due to low ratings. They also failed to inform drivers about the automated decision making.

Here is the statement from the Dutch data protection authority:

   Uber made fully automated decisions regarding drivers. In cases of suspected fraud or excessively low customer ratings, driver accounts were automatically temporarily deactivated or, in the case of persistently low ratings, permanently deactivated. As a result, their income from Uber ceased during the deactivation period.
 
   Uber thereby violated the ban on fully automated decision-making under the General Data Protection Regulation (GDPR). The AP also found that Uber failed to adequately inform drivers about the automated decision-making. Uber has since ceased the violations.

Reference to the law that was broken (GDPR): [2][3]

   Article 22.1: The data subject shall have the right not to be subject to a decision based solely on automated processing, including profiling, which produces legal effects concerning him or her or similarly significantly affects him or her.

   Article 13.2f: In addition to the information referred to in paragraph 1, the controller shall, at the time when personal data are obtained, provide the data subject with the following further information necessary to ensure fair and transparent processing: [...] the existence of automated decision-making, including profiling, referred to in Article 22(1) and (4) and, at least in those cases, meaningful information about the logic involved, as well as the significance and the envisaged consequences of such processing for the data subject.

[1]: https://www.autoriteitpersoonsgegevens.nl/actueel/uber-krijg...

[2]: https://gdpr-info.eu/art-22-gdpr/