You get internet service to your iPad and laptop. Can you watch Netflix and Amazon on those devices or is it blocked somehow?
Did streaming Netflix and Amazon to that TV work before your ISP switch? It's not uncommon for the streaming apps in smart TVs to stop working because the services make changes and the TV maker doesn't update the app to match.
Does your TV have any internet connectivity at all? Can you stream other services, or connect to the Samsung update server?
If your TV can't connect to the internet at all, there are a number of possible causes. First, it may not be receiving a strong enough wireless signal; that could be true even if your other devices can connect because the TV is in a bad location or doesn't have as good a wireless circuit. Second, you may need to configure the TV to use your network and enter a password. Finally, it's possible that the TV is incompatible with the wireless connectivity you have, most likely through a wireless router provided by Mediacom.
Somebody already suggested using an Ethernet connection. That's certainly something to try; in general it's more reliable than wireless. The catches: the TV may be too far away from the router for it to be feasible, and some new TVs only have wireless and lack wired capability.
If all else fails: buy a Chromecast or a Fire TV or a Roku. Stream with that and ignore the TV's smart features. Odds are you'll have to do that within two years anyway because TVs rarely get software updates.