Need to leave as bill too much

[Anna16]

My contract finishes 21 Nov 

my payments have gone up this month due to inflation. 
I need to leave ASAP, 

mots my daughter phone and she only uses on average 13GB data a mth she has a contact for 60GB and need to leave to sim only been told on the 21oct but looking it says 21 November.

please can you advise what I can do she doesn’t require a new phone just sim only abs I can move to another company for a lot less by the looks of it! So how do I terminate this contract! Many thanks 

[MI5 · Accepted solution]

@Anna16 

You can upgrade to a sim only at anytime you wish but you must pay off what's owed on the phone first, or wait until the last device payment is made.

You can upgrade to a sim only in your MyO2.

If you wish to leave, how to cancel here Guide: Cancelling Your Contract