SIM only contract end

[countyexile]

I am a Virgin Media Volt customer and switched from Virgin Mobile sim only to O2 sim only 18 months ago with the contract ending on 7 May.  I understand after that date it will switch to a monthly rolling contract on the same terms unless I do anything to change it.  The current contract is £30 per month with 250gb data, which I don't need as I rarely use more than 2gb per month. The cheapest deal showing on the O2 website is £17.99 per month with 12gb data (doubled to 24gb as I am a Volt customer), although much cheaper deals appear to be available through comparison sites. (15gb for £7.99 per month for example - not sure if that would be doubled under the Volt deal).  My main question though is how soon before the contract end date can I set up a new contract to start from 7 May without incurring early settlement charges. Do I have to wait right up until the contract end date?  Scanned the O2 "help" pages and  virtual assistant without success and it seems near impossible to get any help from O2 without phoning. Can't seem to find any email contact address or Live Chat options.

[Enlli]

You can use the likes of USwitch to get the cheap deal.

The site will pass you through to O2 where you can select being and existing customer and upgrade.

You will go on the new plan and all your Volt benefits will transfer.

Did it myself last month.

[countyexile]

Thanks. Did you have to wait until the existing contract had ended before you could do it or can you do it in advance without incurring early settlement fees?

[MI5]

@countyexile 

You can do it at anytime but you will be charged up to your end date regardless.