You can use @artesea ’s mighty effort to find out what’s supposed to be on NowTV on what dates:-
Type ‘Modern Family’ into the Search box, and you will see that Series 7, 8, and 9 should be there.
@artesea ’s effort is unofficial, as he says, but this is an extract of information from the programmes index on NowTV’s servers.
What NowTV say should be there, as shown by this website, does not always correspond with what is there when you look for it, but at least you know there is an error, and you can point NowTV to that error and get them to fix it.
Hopefully by actually making the episodes available, rather that by changing the index.
Season 10 isn’t there, because it is not (yet?) a box set, but is going through on a broadcast schedule where each episode has about 28 days’ catchup, so you will only ever get it about 5 episodes back, max, at the moment.