What happens once my contract ends?

[Kreq]

So I've been on an 24 month plan with O2 and this month is the last month. 

I plan on getting a new monthly plan with a new phone because I want to upgrade and also currently I am paying £40 a month for the past 24 months which at the time was worth but not anymore.

But the question is what happens after this last monthly payment? Does my plan (data, texts, etc) end? Can I sell the phone now that I've paid every monthly payment?

[MI5 · Accepted solution]

@Kreq 

Your contract continues on a rolling 30 day contract until you upgrade.

You can sell your old phone once paid for as it's yours.

Guide: Upgrading Your O2 Phone 

[Kreq]

So I'll still have a plan for the next 30 days and then after 30 days its finished? Or does it keep charging me £40 a month.

[MI5]

@Kreq 

You can upgrade now (1 month early). 

If you don't upgrade, you will be charged the same again next month if on a standard contract or just the airtime tariff if on refresh.

Guide: How does O2 Refresh work?