Hi @Anonymous User
Down & Up speeds will be dependent on how far your home is away from the local green BT cabinet and the condition of the telephone cable between the cabinet and your home.
When you go through the sign up process on the NOW website it will give you an indication of your guaranteed internet speeds at your post code address (if you are not happy with the figures then don't proceed with the order).
From my understanding NOW have no cap on the down & up speeds or upper limit cap for the amount of data consumed from my knowledge.
Well i am a heavy down users (don't think i am close to 400GB at a calculated guess i am between 180 to 200 GB per month) and haven't been penalised for the 3 years i have been with NOW.
if you need more information or reassurances then you will be better off asking the NOW Broadband Team directly using one of the communication methods in this link page below.
https://help.nowtv.com/article/how-to-submit-a-broadband-complaint1
