^† RPI/CPI Price Increase - Each year, your Pay Monthly airtime tariff will be adjusted according to the Retail Price Index (O2, Three and Vodafone) or Consumer Price Index (EE) rate of inflation. Your bill will be adjusted in March (EE), April (O2 & Vodafone) and May (Three) by the rate announced in January (EE & Three), February (O2) and March (Vodafone) that year (plus 3.9% on EE).