I only just got round to my halloween tasks and i already bought a spooky shot a few days ago and now i only have 3 credits to afford a new one and around 30.000xp to level up to get more credits.

So basically I have bought one, tried it and used it in battle. but the task still remains

Sense. This makes none. Sorry about that, and its done now anyways

Born_dead, did you do all this whilst the task was there, or did you have the weapon before it?

Yes I had bought the weapon previously before i started the halloween tasks

If you had and used the weapon whilst the task was present then it should have registered and completed the task. However, if you used the weapon before the task appeared then you will need to purchase another one and complete the tasks' steps.

I had bought one, then when the task came up, it was still in my inventory is what i mean