fraudulent charges

I had a call a few weeks  from xfnity from a rep who refused to give me his name but instead asked for my account number and email address and claimed that I had unused modem that I did not return. I said what equipment, he said he would send me pictures if only I gave him my info. I said, sounds suspicious, send any info to my account on file and they immediately disconnected. Needless to say, I did not get any emails. 

I then immediately reached out to cut to your customer service via chat who verified that was not normal xfnity procedures and that they can see that I NEVER had an xfinity modem and have no outstanding equipment. He did try to sell me a new package but I declined.

Today I got my new bill and it says $7.85 for unreturned equipment. I went into a chat and they asked for the receipt that I gave them, and now say they have undisclosed unreturned equipment.

How did that undisclosed equipment show up between last week when they verified I had no outstanding equipment and this week?

When I asked that question the rep transferred me to someone else who “is checking on it” but after 10 minutes clearly is not doing anything.

I am really fed up for these fraudulent issues with xfinity.