How can I play a message if a command block isn't activated?

It requires a redstone signal but I have commands for it. Just levels though I'm still getting scoreboard. You need 2 different command blocks at the front before any others (Only if you make it cost an amount)

Command 1: /tellraw @p[lm=(Level Required *Or Higher*)] 
Command 2: /tellraw @p[l=(Level if too high)]

OK, lets say you press a button to get the class. The button powers some restone. One branch leads to the command block, that gives you, say, an iron chestplate, if you have over 5 levels of xp:/give @p minecraft:iron_chestplate[lm=5] Now, the second branch takes away the xp:/xp -5l[lm=5] Now, put a comporator facing out of the command block that gives you the chest plate. The comporator powers more redstone. Now, lets visit the third branch of restone. It leads to a command block that tells you it wasn't a succes:/tellraw @p text:"" You did not have enough xp. Make sure that this third branch has, say, 3 reapeters at full ticks. Now, lets visit the first and second line. They don't have any restone repeaters. They lead to a piston that somehow disrupts the third restone wire(I will leave that up to you, so it is of conveniance) You must time it so if the person has enough xp, the wire leading from the kit command blocks will push a piston or whatever, disrupting the restone signal, then the other restone signal comes through, going for the /tellraw command block, hits the piston, is stopped, and then the piston retracts. I know this will work, but all the text way be a bit scatterbrained! I hope this works for you!

If you have a comparator outputting from said command block if will toggle on or off, depending on if the command block outputted sucessfully.If that is connected to a block with a redstone torch on it, then it will invert the signal. This signal can be sent to another command block that can display your message.