Having used all my data allowance I'm having difficulty buying an add on. When I try either by the app or online it keeps telling me it doesn't recognise the device. It says it may be because I'm connected to wifi. I have disconnected from wifi and attempting to connect via mobile data but with no success. When I log into my account online I cannot find an option to just buy data. If I make a payment to my account there is no way of allocating this to purely buy data.
Can anyone help as I don't really fancy paying £3 a day for the next 12 days!