Abnormal tire wear and need some advice

Okay so in November I bought a 2007 Tacoma Prerunner


On April 24 I had 265/75/16 Toyo Open Country AT II, 16" Pro Comp 7089, and Bilstein 5100s installed at Low Range 4x4 in Wilmington NC. Their machine was out so they set up an appointment for me at Sears to get an alignment done.



Loving the new look and fast forwarding to 3 days ago.

After going surfing I came home and I was like damn my tires are dirty after cleaning my truck the day prior. Upon closer inspection I noticed that about half the tread was gone on both outside edges of my front tires. This worried me as I had only driven 2347 miles since I had the tires installed. So I went up stairs and did a quick google search. After becoming "highly educated" I called sears and said there was a problem. They said they couldn't do anything without seeing the truck. I had plans to leave the next day to drive back to wilmington to go back to school (i live on the outer banks 240 miles away). I then sat down in front of my truck and noticed visually the tires sitting like this \ / obvious not that bad but you get the point. Two days ago I drove back to Wilmington getting the worst MPG I have ever gotten

So today I went to sears so they could look at it. They Measured the tread depth as
DF 7/32" 8/32" 9/32" PF Same

DR 12/32" all the way across and PR was the same.

The man said the tires were fine, the wear was not due to the alignment and that it could be the shocks or something. After explaining I replaced the shocks when I replaced the tires he said that there could be tons of "other stuff" that could have caused it. I told him to sit down, to just look at the tire angles and he explained you couldn't see anything that way. A tech then comes out and puts my truck on the lift. I followed him in to get a surfboard and some skimboards out of the back so nothing could throw the alignment off. He asked if the lady out front had gotten my phone number, i said no and told him i was gonna watch. When he went to adjust the alignment I quickly took this picture..

and good thing I did cause when he was finished he told me he "forgot" to save the before stats. While he was adjusting something he asked how the truck was on the beach...uh its a two wheel drive truck. Oh yea i knew that..

He then went on to tell me that i should get an alignment ever 500 miles or once a month and to get my tires rotated every 1500 miles.

I just want to know what to do? And wanted some advice before I went to talk to the store manager to ask for replacement tires.

Thanks in advance, Shawn