The free VOD 5GB is confusing. I somehow have it listed as one of my data quotas even though I don't use or subscribe to the services which the quota is meant for, namely iFlix, Viu, ErosNow and Hopster. To make the matter more confusing, the quota has depleted by 520MB, not sure how it got depleted when I don't use these services. Anyone has any idea what could have used up this quota? I do subscribe to their Spotify Premium though.

I don't think Spotify consumes this VOD quota, and Spotify is supposed to be on promotion with unlimited data until September 30th, after which a cap of 15GB applies, separate from all the other data caps. And that's the mystery. What on earth is using the VOD data cap. Anyhow, perhaps I shouldn't care. But I'm bothered by the mystery. Might give their CS a call when I get a moment to spare.

Yes, you can. Though you'll have more devices you can sign on using your account if you signed up using username and password instead of single-sign on with Facebook.