I have the same problem. I bought a 5GB add on last night because I had run out of data. My new 500GB was expected this morning but it isn't there and it says next renewal 26th Apr but it hasn't given me the 26th Mar data. I can't text as this data is for my dongle not a phone.
I don't see any option to start the data from there sorry. The progress bar is as below but there should now be 500GB on it. You can see from the history I bought an extra 100GB a few days ago because I had run out so I've been waiting for the renewal urgently.
Start date 21/03/2020
Start date 26/02/2020
Start date 26/01/2020
I unplugges the dongle and plugged it back in but not sure if thsi will have done anything. It is working fine as it still has 3GB data from the top up. My EE account still shows only the 3GB data and next renewal 26th April so it's just completely missed out March
by Krisj1 Wednesday