Comcast stopped working on older, not so smart Vizio TV

Hi Eric, I have an older Vizor not so smart tV.  Worked fine with comcast, well, until yesterday.  Now can not get back to comcast.  I do not think any cables were changed or remove.  I have tried to tighteb everything.  I have tried to find the compatible Comcast to Vizio number, but perhaps this was a mistake.  Yup, there may be a component that went bad, but I think that unlikely.  I am so frustrated, and have spent more time than I would like to acknowledge, with no fix to this point.  Any suggestions as an appropriate next step would be much appreciated.