Myself & my wife recently (May 4th) both upgraded our phones online with O2.
We have received our new phones no problem.
My O2 is now showing 2 x monthly accounts?
Doesn't new upgraded phone & monthly tariff replace old tariff?
Why are we being charged 2 x monthly account fees?
I'm little bit confused
You will have 2 charges and Direct Debits on for the tariff and one for the device plan..
Full details can be found here Guide: How does O2 Refresh work?
Contact O2 and migrate your old numbers to the new accounts.
Somehow you got a new contract and not an upgrade Guide: Migration & porting into O2
When you 'upgraded', you will have had a closing account for the previous tariff, and a new one for the new tariff, @jamesstevens71 - unless O2 sold you each a new phone with a new number, and have left it to you to swap numbers from old to new (unlikely, but it can happen if a new contract is cheaper than upgrading your existing contract).
If you have not already, you can call O2's Sales Team in the morning on 0800 081 0255 or drop them a message on Social Media, links below.
If you did buy new contracts rather than upgrading your existing contracts, the guide to do a number swap here Guide: Sim Swap: a mini guide 2017 update includes the info that will make O2 close the account you don't need whilst moving your number to the new SIM in the new phone. This will also generate a final bill to balance the books on O2's side, which happens because you pay a month in advance for an O2 Contract phone. Ditto for your wife's phone to sort that one out too. Good luck!