I was sent some equipment that I did not request

This week I was sent some Xfinity equipment (I think it's called an XiD-C unit) that I did not order.  On Thursday I returned what I am pretty sure is an older version of this equipment via drop off at my local Comcast store. Last week I replaced the old (XiD-C?) unit with a new X1 box for use with a second TV downstairs in my home and in the course of getting it set up the customer service rep I was talking to made a few changes to my account and service with the result of me getting faster Internet whilst paying less on my monthly bill.  Because I was in my basement, the phone connection was (to put it mildly) not good and both the customer service rep and I had a lot of trouble hearing each other over the course of the call, and I think she said I should be expecting a new gateway/modem (maybe, as I wrote before, I couldn't hear her at times, so maybe nothing at all), so that is what I was expecting when I got an email about my "new X1 equipment" being shipped. Anyway, I assume I have to drop this one off at the Comcast store as well, since I am pretty sure I do not need it. I tried taking up this issue with the AI Assistant, but since it's not a simple Yes/No issue "They" were no help. How can I figure out if I am supposed to be getting some new equipment or not and if so, what it is supposed to be?