If both sims were payandgo you only top up the one you want to use so you won't be paying both. If one is a contract you need to give 30 days notice by calling customer service.
If you want to keep your original number just call into your O2 store. They will supply a new sim free and swap your number over for you.
Hello @Anonymous how are you getting on? Did you manage to find out all the info you needed about your tariffs?
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