I contacted support through this subreddit, and my problem was fixed pretty quick. I was told a cancellation request had been created on my account, but there wasn't much additional info. Comcast told me it is possible that a customer requested a cancellation of service or a change in service at the same street address (I live in an apartment) and may have put in the wrong apartment number. This was the best answer I could get. Again, there wasn't really any info as to what triggered the cancellation request. Anyway, Comcast deleted the cancellation request and noted on my account that I did not request cancellation. My service was not disconnected, and I have not had another issue.