Comcast Prepaid Internet in Apartment

So I found out comcast had prepaid internet packages. In my area its either Frontier, Hughsnet, or comcast. I have dish cable right now with frontier. Frontier internet goes out at least 1 time a day. I'm ready to be done with them. I've been done with my Dish 2 year contract since June so I'm free to leave and I plan on leaving.

So I did some searching and found this from comcast:

• http://www.xfinityprepaid.com/internet/eng/internet_index.html

$45 a month for up to 20mbps speeds with a free modem. I have frontier right now and pay $45 a month for 9-12mbps thats not very stable. So I thought it was a no brainer switch.

I want to cut the cord. I plan on having Netflix, Amazon Prime video, Directv Now or PS Vue.

My concern comes with installing the internet. It's an aparment building. Older. My neighbors have Comcast and Frontier around us. The Apartments are all in a row. There's maybe 8 of us side by side. On the back of the apartments you can see the cables come from a pole to the back of the apartments. I can see where our dish cable comes in through the back into our living room then into our bedroom. But in our bedroom upstairs theres a cable that comes in from the ceiling in each of the bedrooms. I'm wondering if this might be the old comcast hookup. Just wondering how hard its going to be to hook this up. I know dish and comcast cant exist on the same coaxial cable but we are dropping dish. I know my worst case scenario is pay the $60 installation fee if I can't do it my self. Just wondering if anyone had any thoughts. The Internet starter kit is coming tomorrow (26th).