Can someone explain to me how the O2 'pay and go' tariffs work? If I was on say a £10-£14 a moth pay and go tariff: I put in my £10 at the start of the month and get my free allowance (300 texts, 50 mins etc). Can I use my allowance for the month, miss the next monthly top-up then start eating in to the £10 credit? Then when the credit is depleted I can put in another £10 at my convenience, get another allowance, rinse and repeat? Surely if I am forced to top up every month it is just another contract? Can someone clarify this please?