Pay more than upfront cost? (Phone only)

[Floki]

I am looking at a phone that I wish to buy and only for the phone itself, as I'm happy with the contract sim I'm on.
My question I ask:
Is it possible to pay more than the upfront cost? As it is possible to change 'Spread the cost over' 
From what I see, the option to edit the 'upfront cost' doesn't show online.

Or id this something I can only do in stores?

[Cleoriff · Accepted solution]

Hi @Floki 

You need to look at O2's custom plans where you decide what you want to pay upfront etc.

https://www.o2.co.uk/custom-plans 

[jonsie]

You couldn't keep your current tariff, all phones come with their own tariffs to choose from unless you pay the full phone price