How to get attention to complaint about technician

On Thursday 2/18, we had an appointment in the AM with Technician "E". He replaced our modem.

On Friday 2/19 at 5:25pm, our security camera caught someone going between our fence and bushes into our backyard. They remained off camera for about 10 seconds, then slowly made their way back up the driveway to their vehicle. They were wearing khakis and a black hoodie with the hood up. There were no badges. He never knocked on our door; we were home. He got in the vehicle and when he drove away, we saw it was white with red Xfinity on the side.  We shall call this guy Technician "C" for creepy.

Technician C was NOT the same as Technician E.  They had different skin color. 

We called the police and filed a police report. The police department gave us an incident number but won't be able to do anything more. 

We contacted Xfinity chat who told us to call. We talked to a rep who put us on hold but tried to convince us Technician C was there for an appointment. We had to repeat it was two different days. She put us on hold and never returned. We called back and the new rep understood our concern. He said the only way to resolve this was to go into the local Xfinity store. He confirmed there was no scheduled visit to our home.

So now I have to go into the Xfinity store - in a pandemic, while living with someone who is immunocompromised - to find out who the heII was on our property and why. 

There has GOT to be another way to resolve this.