WHAT CAR STEREO KEEPS GOING INTO DEMO MODE WHEN THE IGNITION GETS TURNED BACK ON

You most likely have the 12 volt permanent connected to the switched supply lead you need to identify which wire requires the permanent and the wire that requires 12 volt switched this will only appear when you turn your car key to acc position , it's normally a yellow or orange wire your looking for but check your models schematic.

have a lookn on the wireing on the back of the unit. you should have 3 cables that are dedicated to powering the unit. one is 12v constant power, one is your ignition and the other your earth. ensure that your 12v power cable and ignition cable are connected up correctly.

go back to the stereo shop and make sure they connected the memory wire on the unit to a constant 12v source

This is happeneing because the stereo does not have a battery power connections. The yellow wire is for a constant 12 volt connection. This connection is for the stereo's memory.

you'll notice a connector on yellow and red wire, these are battery connection and ignition.connect the red onto red and red onto yellow....thats it....it is also shown on operation manual, ISO CONNECTION option 2.

you put something in the blue input thing
that puts the stereo in demo mode

It sounds like it is in demo mode. Try going back into the menu and find the demo mode turn off.

to turn off demo mode put radio into stand by were it is running demo mode and hold number 6 till it switches off. As for the key problem its the key that is making the key live connection on your model of car so this can not be changed. sorry

OK,
Please make sure Yellow wire (back up supply) is connected with Ever-12 Volt line (should not switch off with ignition) and press DSPL button to et display on clock.