If you're playing last season, pokeball is just lootbox renamed. You have to mine 6500 raw block to get one.
I'm not sure if you understand what i mean by raw block so imma explain anyway. Raw block are the block you break by yourself, not your enchantment. Like when you hit 1 block and your explosion enchantment break blocks around you in 5 blocks radius. That counted as 1 raw block.
It's best to have boomerang to get more rawblock. Or just get pick only with jackhammer and gem booster (i believe this is the enchantment to decrease the requirement to earn pokeball). Not sure if its really effective because me and my friend tried it on last season, me with no gem booster and my friend with maxed gem booster, we both get lootbox at the same block and its 6500, no decrease at all.