Audio/Video gets out of sync

I have the X1 box and an issue has developed with it in the past month. The audio/video gets out of sync enough that it makes watching TV painful! It does it on all channels and only on this box. Others boxes are fine. I can restart the box and it is fine until the next evening. Don't mind restarting it but it may be about to go out.

I am over an hour away from the nearest Comcast office and I am wondering do they mail replacement boxes out?

Thanks for any help-!