150 Mbps Connect Internet plan sunsetted. Replaced by a false promise of 300 Mbps

Where do I begin? The speed issue is not unique to my home Internet. Others have reported this problem. I have the very same slow speed problem with Xfinity Internet at another residence. My ARRIS gateway, although several years old, is perfectly capable of achieving speeds of 600 mbps, according to the manufacturer. In addition to slow Internet speeds, my Internet is cutting in and out every several minutes. I attempted to change my current gateway with two other ARRIS devices but due to the abject ineptitude of the various Xfinity chat and phone agents I interacted the endeavor proved unsuccessful. One chat agent, whom I will be filing a formal complaint against, after wasting my time by failing to add the new gateway, abruptly ended the chat session prematurely after instructing me to visit my local Xfinity store to remedy the issue. I have had these technical issues with my Xfinity Internet from the moment I was switched from the Xfinity 150 mbps to the 300 mbps Xfinity Internet plan. I have spent hours of wasted time in chat sessions and on the phone with Xfinity chat and phone agents and supervisors to no avail.

This issue has nothing whatsoever to do with my wall outlet.

I am constantly amazed but not amused by the inability of Xfinity agents to retain pertinent information, focus their direct attention on the issue at hand and perform even the most rudimentary critical thinking procedures. Routinely, if the information isn't in a Xfinity employee handbook, the Xfinity employee becomes cerebrally challenged, unable to think outside the box in an effort to apply deductive reasoning in an effort to directly solve the problem.