So I have to grind a few levels, just to have enough essence to upgrade a champion mastery.

{quoted}

bullshit because I just played 20 games, leveled up once, and I only got 4 champion shards and they all disenchanted for 90 BE.

Meanwhile, it cost 3250 to go from level 5 to 6

20 games, assume 100 per game + a 200 first win of the day. I'd have 2200 by now.

That is one hell of a lie because none of the champ shards disenchant for that low. do research before you lie.