ASUS False accusations of mainboard damage , Internet

A little over a week ago I placed an order for over $2000 worth of computer hardware.  I am a computer repair shop/builder/consultant owner.  I ordered my products from a very reputable firm and I received the products promptly.  All the hardware was intact and undamaged or so I thought.  After assembling the new computer for a business customer I walked through my assembly as I always do, I check and re-check everything I have done before initial power up to make sure that all connections, motherboard spacerc, RAM, processor etc, is installed correctly and that everything is where it's supposed to be.  I plugged the main power cord in and observed the motherboard function lights as I switched the power supply unit to the on position for the first time.  All is well at this point,  then the fun starts. 

I go over the connections one more time to make sure everything is right and confirm that yes, all is well.  So, I push the unit power on button and the case fans immediately start spinning, the lights on the motherboard turn to green as they are supposed to, the monitor at this point is not showing a picture but what I do see is a cloud of smoke and the acrid smell of electronics smoke pouring off the motherboard.  I immediately yank the plug out of the wall and begin to try to figure what happened.  Well, after rechecking my work over and over and having a colleague look it over more than once, the only thing we can ascertain is that the motherboard has some sort of problem.  So, I disassemble the computer and send the motherboard back, (at my expense) to ASUS for an RMA and low and behold on March 20th, 2013 I got an email from them stating that there is "trace" damage to the board and it's not covered under their warranty.  They want another $120.00US to replace the board as it is destroyed. 

Well, I emailed them back and told them it was not my fault, so they accused me of overclocking the board then asked me for $90.00US instead of the $120.  I have in the past damaged motherboards by accident and I have paid their fee to be replaced as I should.  This time with the accusation of overclocking the board and burning it up is beyond anything I can put up with.  I did nothing to this board, in fact, I never saw anything on the monitor that even looked like a POST screen or anything with the ability to overclock this board.  I have an irate customer who needs this computer for his business and I am getting nowhere with this with ASUS, I just want to get their name out there for people to be careful if they RMA something with them, make sure you take pictures and document your work as you go along or you might just be sorry you ever did business with ASUS