Hah! I just recently got to switch off Comcast to a newer local fiber company. Comcast emailed and texted me for weeks telling me to return their equipment that I never had, but even their website showed I had nothing to return so I ignored it. Eventually the emails changed to “you’ve been charged”, so I called to complain. They assured me that I wasn’t actually charged, and then realized they owed me a prorated refund since I cancelled in the middle of a billing cycle. They absolutely weren’t going to give that back unless I called.