Good afternoon, my name is ***** ***** I will assist with your query today.
When you press the menu button on the remote does the Samsung Menu display?
Sorry for the short delay in responding.
Press the exit button on your remote twice, and tell me what is now shown on the TV.
With regard to the volume symbol are you able to advise what it looks like, is it a speaker icon?
Can you also advise if your using a sound bar \ sound system external to the TV?
Ok, can you confirm if it is still present when you press the mute button?
Ok it sounds like the software has become corrupt, the best thing to do is a factory reset.
Within menu select the support option, then self diagnoses
Under the sub menu should be an option for factory reset
When prompted enter the PIN, by default this is 0000
The TV will restart itself and take about 2 minutes to complete, after which point you will need to retune, but the fault should have cleared.