Judgment of the General Court (Eighth Chamber) of 21 December 2021.#Datax sp. z o.o. v European Research Executive Agency.#Arbitration clause – Seventh Framework Programme for research, technological development and demonstration activities (2007-2013) – HELP and GreenNets grant agreements – OLAF’s investigation – Personnel costs – Burden of proof – Reliability of timesheets – Ineligibility of costs declared by the beneficiary – Request for recovery – Debit notes – Limitation – Reasonable time – Proportionality.#Case T-381/20.