Missing Achievement Item

I completed my rank 3 hunting log for the maelstrom and received the achievement "Bump on a log: maelstrom" but upon completing the achievement I did not receive the item "Mammet #003L"
Can anyone tell me how I'm supposed to get the item, I checked my inventory and the was no item in there I could use to receive the item. Any help would be great.

Talk to Jonathas at Apakallu Falls in Old Gridania. You 'Tell him the story' of your great achievement and he gives you the item.