Disputed charge sent to collections despite Xfinity confirming it was a billing error

I am writing to formally dispute a charge that was sent to a third-party collection agency even though Xfinity's own representatives confirmed, in writing, that it was a billing error and that I did not owe it.

Here is what happened, with dates:

In a chat on September 20, 2025, an Xfinity representative told me the disputed balance was appearing because of a "technical glitch," that I did not need to pay anything, that a confirmation email had been sent, and that the amount would be removed within 24–48 hours.

In a second chat on October 17, 2025, another Xfinity representative again confirmed there was no need to pay, said the charge would be waived within 24 hours, and stated the account notes had been updated so I would no longer be notified about these charges.

I saved the full transcripts of both conversations.

Despite these written assurances, the charge was never corrected, I never received the confirmation email I was promised, and the balance has now been referred to a collection agency (Harris & Harris), which is contacting me for $71.47. The amount has also been inconsistent over time — it appeared at different points as $41.98, then $53.67, now $71.47.

The underlying charge relates to a mobile line I was told would be free for the first year. The line was active for less than a year.

I would like the Digital Care Team to: (1) recall this account from collections, (2) correct the billing error and zero out the balance as your representatives already confirmed, and (3) confirm in writing that nothing negative has been or will be reported to the credit bureaus.

I am currently abroad and can only handle this online. I have all transcripts ready to share. Please let me know how to proceed.