I recently purchased a SOTA Arms assembled upper receiver directly from their website, and took it and all my gunsmith to get everything tightened to spec. As he was torque-ing the barrel nut the upper split along the barrel chamber and the pivot and take down pins. The upper was mounted in a calm shell style vise clamp. I immediately contacted SOTA arms and explained what happened. When they finally contacted me, they informed me that it was the gunsmith's fault, he over-tightened the barrel nut. I forwarded the emails to my smith and he responded buy sending pictures of all the equipment used in all builds. (By the way, this was my third build with this smith. 2 PSA uppers and one from Global Arms, no breaks.) SOTA Arms refused to reply to him. Sent an email saying I was unhappy with product and customer service and would state so in my review. I got a nasty phone call from a rep accusing me of slandering them, saying his photo of a block of aluminum and an out of focus piece of paper was his confirmation of 7075 aluminum. My smith conducted an independent test due to their lack of communication, it came back that it was not. He said his photo was proof enough and he would send me, "a confirmation hand written in crayon so I would smile."
My gunsmith did replace the upper with one of his shop's own, and surprise surprise it didn't break either.

Has anyone else had a problem with SOTA Arms? I read several reviews here and on other forums with mixed reviews. Unfortunately, I didn't look them up through the BBB until after and I found that they have several complaints against them. Any suggestions as to how I can get them accept responsibility for their product?

Lesson learned... buyer beware! There's a reason it was so cheap.

I purchased one of their complete uppers - fitted to a lower and works fine. No problems.

Also purchased two SOTA uppers and barreled them with no drama. Barrels snugged up without issue.

Have had no problems with their products and will purchase from them again.

I have 2 sota arms uppers also.No complaints here.I think your smith may have been  a bit over zealous, but thats only my opinion.