Nissan Qashqai 1.2 Tekna CVT

We took the delivery of the new Nissan Qashqai 1.2 Tekna CVT on 01-02-2020. Since delivery, the car clock has been many hours fast, almost right, and many hours slow along with everything in between. The car was taken back to Nissan dealer twice, who updated various system. The time only remains correct for a day thereafter the same problem again. The reason I am writing to you its because I am not getting any joy from the Nissan dealer.