My hard mode Titan quest is glitched

on ps3
Time: can not remember
Frequency:every time i attempt to complete quest
World name:Faerie
Character name:Magna Sanatore
NPC name:no npc
Monster name:one monster in area but killed it before trying to attune crystal
Class/Level: WHM/50
Party or solo:solo
In-game time:can not remember
Area and coordinates: Eastern La Noscea X:24 Y:8
Steps: quest name: In a Titan Spot
Attune to crystal to complete quest it will tell me that the quest has been completed and it has been added to my duty finder. i go to check duty finder and it hasn't been added go to journal and quest is there. attempt again same thing happens. i have tried zoning relogging still same outcome. the first time i attuned to crystal i was using duty finder to search for garuda run, i don't know if that might have glitched my quest. but it would be greatly appreciated if a GM would be able to help me. Please and Thank You.

Your inventory is full. Discard an item and it should fix it.

omg dude give me a hug now!!!

omg i love you so much right now, i had full inv too and have been unable to finish this quest for last 30hrs.. so glad i saw this thread

thank you so much never even thought that could be the problem.