Getting the proper attention of the person you need to can be difficult.
The first thing you have to convince them of is the problem is not with your local connection (making sure it is not first). The problem lies in their network or at their network edge. You have to keep repeating that until they get it. You have to be persistent that first tier support cannot help with this problem. Keep repeating it.
You have to keep asking the person you are talking to if they can actually help with a problem which does not have anything to do with the "first mile" (i.e. your connection to them). You keep pushing them for an answer and when they finally admit they cannot help with that, then you press to talk to someone who can.
The job of first tier support is to get you off of the phone and convince you there is no problem.
The next problem you will run into is the ISP which will or cannot do anything about the problem. Check your contract with them. It will normally only cover your local connection to them. This means as long as you have a good connection to them, they have no responsibility to discuss anything else with you.
All that said. The state of the Internet is pretty bad right now due to all the damage done to the telecommunication infrastructure by horrid weather that continues to plague the U.S. In most cases, there is little anyone can do about the congestion problems as the infrastructure does its best to absorb data from the broken systems into the already over loaded working systems.
Right now, the best thing that could happen would be for Youtube, Netflix, and Hulu to shutdown for a couple of weeks to reduce the stress on the networks until they can be repaired.