Charged $100 for a technician visit after being assured that there would be no charge. OUTRAGEOUS.

After I upgraded my service to 1gig and installed the new router at home, I was having interruptions in service and dropouts on my internet connection many times during the work day, seriously disrupting my work-from-home ability.   I contacted Xfinity support and they said they would dispatch a technician to troubleshoot the issue.  I asked at the time if there would be any charge for the technician visit and the phone support person assured me there would be no charge.  The technician came by, checked everything on my end and found no issues.  The tech said that he would elevate the ticket on Xfinity's end to continue troubleshooting the problem.   Around 24 hours later, I received a call from a higher-level support person saying that they had found the issue on their end and confirmed with me that my connection was now solid.

Now, nearly a month later, I find an unexpected and unwelcome $100 charge on my bill.  So I'm expected to pay $100 for Xfinity to troubleshoot a problem that was completely on their back end and their responsibility?  OUTRAGEOUS.

Please remove this unwarranted charge from my bill as soon as possible.