Alright so, I sort of understand about the whole transfer/linking thing, (key word: Sort of)

My old account, the one I'm working on reactivating, hasn't been touched in 3 years now. When I go to 'transfer' onto this ID, it tells me that it can't be done and i have to talk to customer support. Is that because the character i'm trying to transfer over hasn't been reactivated yet, or...?