Re: missing olive pit seed packet
From Arena you get a total of 20+30+50+150+200 = 450 seed packets after reaching 500 crowns.
It takes 250 seed packets to unlock Olive Pit and 350 seeds to get it to level 4.
Assuming you did the Quest for 50 Olive Pit seeds you should have earned: 450 + 50 = 500 seed packets.
To unlock Olive Pit and reach the current level you have it takes: 250 + 350 + 13 = 613 seed packets.
Which means you got 113 seed packets in Pinata Parties and the store. So to me everything looks fine (of course I don't know how many gems you spend on Olive Pit seed packets)
If you still think you didn't get the reward at 300 crowns (150 seeds) contact EA Help: https://help.ea.com/en/popcap/plants-vs-zombies-2/