Travel Bolt-on confusion

[RicWalLar]

I'm travelling to USA for just over 3 weeks My tariff doesn't include Travel Inclusive so I need the Travel Bolt-on for which I'm charged £6 per day when I use it. I wanted to check how it works so went into my local O2 shop, but they were no help at all (subsequent call to Customer Service confirmed they gave me completely wrong information). I wanted to ensure the £6 charge covers calls made to phones within USA (eg for booking a restaurant table). The shop said it wasn't included & would cost me £2/minute but Customer Service confirmed what I believed & how I read the terms: it is included. After all, it says on the Terms (emphasis added): 

"O2 Travel is the perfect way to stay connected in selected destinations outside our Europe and O2 Travel Inclusive Zones. It costs £6 a day, and that gets you all the data you need, plus unlimited minutes and texts, both where you are and back to the UK.

There's no upper usage limit on data, but data speeds might vary. These allowances won't affect your standard UK allowances. Voicemail (901) is included."

So I've added the Travel Bolt-on to my account.

But Customer Service also said I have 5GB of data already available as a bolt-on to my tariff. But there is absolutely nowhere I can see this and I knew nothing about it. So now I don't know (I was getting a bit confused & didn't ask) whether I'll get this phantom 5GB usage before any £6 charge kicks in! I would think that I should do, though if I make a voice call or text I guess that would trigger the £6. Confused? Moi? 

[RicWalLar]

I guess the answer to that is to turn on Low Data Mode. Background tasks, updates, syncing etc are paused.