Add data to a pre-paid sim on the livres dia 2017 tariff

I think this is not going to float because I just checked nos reputation on consumer sites - nearly ZERO!!!

I have had a livres dia 2017 pre-paid tarrif for years and now I want to occasionally add data. The web login won’t allow me to, neither will the app. When I use the callback, I get someone who can’t speak english - but they happily took all my money in English.

So, any ideas how I can add data please?

I have 3 accounts with nos, my Wife I have just set up with Lyca and I think my 2 nos accounts will be going lyca just as soon as the balance goes to zero.