I'm currently on the old O2 Genie SIM tariff of 300 free texts a month when I top up £10. However, I've just received my free O2 Unlimited SIM card and want to change my current tariff to this one without changing my number. How do I do this? (My phone is a Sony Ericsson K750i if that helps!)
You don't need a new SIM. You can change tariff once a month. You'll find instructions on the O2 web site, in the Pay and Go tariffs section of the help section. Or just call O2 and ask them to change you. Or call the tariff line on 2425.