Bad service, unable to assist with solving my issue

This is the worst service I have received from a service provider. I went to one of their stores and told the agent that I wanted a package for the home and he asked for my address and checked on their system. I was then recommended the home 5G package at 100mbps. I experienced connectivity and speed issues. I then contacted the same agent and he advised that it was because the contract is new and it will get better. After countless calls to customer support and getting them to reset my router, I decided to go back to the store and was told the agent doesn't work there anymore. I explained my issue to another agent and they checked my coverage and told me that I don't have coverage where I stayed. I then requested that they change my package to something that will work where I stayed. I was then referred to customer service and request their retention department. After doing that I was advised that I had to pay 6k+ for early upgrade, I explained the situation and was told there is nothing they can do. I went back to the store, gave them feedback and haven't received assistance to this day.

I am paying for a 100mpbs and I am getting anything from 2mbps to 16mpbs, on a good day I can get 40mbps. Why am I paying for something I am not getting?