UPDATE: Im a dickhead, I contacted them via phone and they were helpful with me.  So for any potential buyers out there CALL them don't email them.  


Just wanted to warn anyone out there of a safety issue I had with an upper I purchased from MAS defense.  I got the upper, and without using it, took it to get cerakoted at a gun smith.  I got a call back from him saying the barrel extension was not tight enough.  (good thing I didn't shoot it)  So I have to pay 35 bucks to fix it.  No big deal, other than MAS defenses' customer service (or lack thereof).  I contacted them 3 times via email, and after a full business week, have not received a response.  I noticed that you cannot leave an honest review on their sight, as if it is less than 5 stars it wont let you post, AND they screen the review before they post.  So DO NOT BE FOOLED BY THEIR FAKE FIVE STAR RATING SYSTEM. I will be reporting them to the BBB first thing on the morrow.  I am writing this out there because I looked into them heavily before settling on them and I did not see anyone write about this.  PLEASE be careful if you order from them, at least get someone who knows what they are doing when it comes to barrels look at it before you shoot it.  I myself will probably go with DD or BCM next time and know for sure Im getting quality and SAFE items.  Thanks

That's surprising, I had contacted them about an issue that turned out not to be one and they responded immediately and didn't even charge me for return shipping.

Glad to hear they got you taken care of.
They answered my email in a couple of days, which during the Black Friday sales.
My upper is great by the way, I just shot it yesterday.