I have had exactly the same problem and despite posting a question on this site and trying to contact EE helpline directly (I could never get through to them), I did not get any further.
As a last resort I phoned my local EE shop and the problem was sorted in a few minutes so 10/10 to the girl at the Carlisle EE shop!!
As I understand it --- You have paid £25 top up into the EE coffers BUT then you have to choose where you want to spend your top up money - is it on data (yes) or top up the phone or pay towards a bill etc etc.
On the screen you have shown in the picture - I think you have to click on the Get Data line.
You then get a Buy Data tab with various options of choosing how much £££ of data you want to buy - I topped up just £10 so there was a £10 button for me to select - not sure if there is a £25 button but if not, presumably you can select the £20 button and still have £5 left in credit?
Click on confirm and it adds it straight away.
This is the gist of how it works as I was talked through it by the EE shop girl and can't remember exactly how it worked but I hope you get the gist and will be able to sort it.
I cannot believe that there are no clear instructions how to do this on the EE site or in the WIFI mini box instructions.
Have you registered on the EE website? Using the MyEE facility once you have registered, I imagine that you can top up £££s and then BUY DATA with your £££s all in one process.
It should NOT be this complicated.
Regards
