From your comment before editing and your comment above, you seem to think I think it's some kind of magical drug. Of course you can gain weight with a caffeine addiction, that doesn't mean caffeine doesn't help weight loss and your case is not evidence that it doesn't. (**EDIT** Also worth noting, if the addiction was met with lots of coffee with milk in, there's a lot of calories in milk...) You need to be doing other things right though. Just Google 'does caffeine help weight loss' and there seem to be lots of articles stating it does and why. I don't think I've found one (and no, I've not looked all that hard) that says it doesn't. Even in this thread most people are saying it's helpful in one way or another, although you state most are saying otherwise?
It's a bit like someone saying walking 30 minutes every day helps weight loss and you saying, 'well I walked an hour every day and gained loads of weight'... yes, maybe you ate McDonald's three times a day! Maybe you had a chocolate addiction! The walking was still better than not walking!