Repeatedly Sent to Collections

I signed up to add service to a second address that I ended up canceling and never setting up. I spoke to a service representative and they cleared the charges from my account. According to the app and all records, I have always been in good standing.

Well this cleared debt was sent to collections anyways and after disputing the claim and contacting Xfinity it was cleared.

Then months later it happened again with a different collections agency and I went through the same process and was told by Xfinity that my charges were cleared and that this would not happen again.

Here we are 3 months later with yet another collections agency calling me to collect a debt I was ensured I did not owe for a service I was never rendered. No one seems to help me, this is never escalated when I ask. Who do I need to talk to fix this? It's impacting my credit and has become enough of a pain that pursuing legal action no longer seems like too much of a hassle.