You may find the following link helpful: http://forums.xfinity.com/t5/Customer-Service/Comcast-Policies/m-p/1969729/highlight/true#M47797
No, Comcast isn't accusing you of anything. Whoever owns the copyright to those movies is accusing you. Comcast is just letting you know that a claim of copyright infringement was made against you.
If you receive a DMCA notification of alleged infringement and you believe in good faith that the allegedly infringing works have been removed or blocked by mistake or misidentification, then you may send a counter notification to Comcast. Upon Comcast's receipt of a counter notification that satisfies the requirements of the DMCA, Comcast will provide a copy of the counter notification to the person who sent the original notification of claimed infringement and will follow the DMCA's procedures with respect to a received counter notification. All counter notifications must satisfy the requirements of Section 512(g)(3) of the U.S. Copyright Act.
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