Battery warranty

I bought a Sabat battery in March 2020 and just before the warranty expires I took it to the dealer for testing. They found it faulty and because it was still in the warranty period, they supp**** me with a new battery, without charge, which was good. But now, 2 and a half months later, that battery is dead and now they say that I don't have a warranty on it, because the warranty of the first battery already expired, so I don't have a warranty on the second battery. My concern is, how do I know that I was not supp**** with a old stock battery, and/or is that batteries just of such bad quality that every second one died in a short period? If batteries is of a good quality, why don't it last longer than the two year warranty? Over the years I found that imported batteries coming with imported vehicles lasts much longer than two years. A pity it is not freely available in our country