Maruti 800 — gearbox oil leakage

a brand new car beAring regn.no TN-O2-AC 9025 WAS DELIVERED TO US BY KAPICO MOTORS CHENNAI ON[protected]. WITHIN 80 KM RUNNING WE FOUND WHILE PARKED AT HOME- OIL LEAKAGE ON 8TH. THEY CAME AND TOOK THE VEHICLE AFTER REPLACEMENT OF THE DRIVE SHAFT OIL SEAL ASSEMBLY AND DELIVERED THE CAR ON 12TH. THE POINT IS HOW CAN SUCH AMAJOR FAULT BE IN A CAR OR HAVE WE BEEN PASSED ON A USED REFURBISHED CAR BY THE MANUFACTURERS THEMSELVES.
AN AGGRIEVED CUSTOMER