Internet Signal Gone for Hours Every Day - Like Clockwork

So I recently helped a family member get Comcast's low-cost $9.99 plan 5 Mbps internet, and every single day the internet signal dies in the late morning / early afternoon and does not come back until very late at night. What's up with this? Poor people don't get internet before midnight, LOL?  Sassy tongue-in-cheek remarks aside, we'd really appreciate any help we can get because they have a daughter who needs it for school and it's very frustraing that after multiple gateway hard resets nothing has improved.