pixalating big time

We are having a pixelating problem big time.  It effects both the internet and the television picture.  We have had numerous visits by technician and nothing is ever improved.  We are fiber optic connected I believe.  We have checked all connections in the house.  We have changed out numerous boxes and modems.   IS there an option to repair at all?  The phone number connect to my account is and we live in .  Thank you.  This problem is causing my son to fall behind in his school work, some of which is online.  I also work at home over the internet and will switch to Infinity if this cannot be solved like today.  Thank you.