They charged me $85.00 to "isolate" a hum on my line, which I had not complained of because I had never noticed it. I requested assistance in improving my slow internet connection speed, which is still the same - slow.

Fight it. If you don't get a good answer from the call center ask for their manager and keep taking it higher until they resolve it. It is easy for the operator of a company to blame it on "company policy". The district manager has a much harder time being unreasonable. Don't raise your voice or don't dare curse. Just tell them that is not an acceptable answer and you would like to speak to their manager. Keep documents of names and pursue it like mad. They will refund it to make you go away. They are in the wrong.