Comcast blocking downloaded updates and adding .part ending after.pkg—why?

Why is Comcast adding a .part ending  after .pkg making my downloaded updates unable to open with the Apple installer? Get info indicates zero content thus Comcast is blocking all of my updates, a problem that has arisen over past few days. No spam settins are set and I have turned off my anti-virus app! I think Comcast is blocking all my downloaded updates. Why? I have used 4 differnt browsers to no avail, please help.

    Regards

    Sternhagen