How do u fix AT&T uverse ondemand when it won't pla the video?

It just says it is finished 8 seconds into the movie and we start it over and than it says finished 8 seconds in again|||I've also seen that on some of the programs I've recorded on the DVR. Don't know why. Since you paid for it, call tech support and see if they can either refund your payment or reset the recording so that you can see it. 800-288-2020.