Weird 430ex II problem out of the box

So I just purchased my first speedlight (430ex II brand new) a few hours ago and ran home and set up my camera (60d) only to find out its not working.

I got it to fire 15 out of 100 shots, the flash bolt in the view finder is flickering, and the shutter speed will jump with it. The camera still recognizes it and I can change all of the settings/zoom etc from the camera. DOF button does the modeling light maybe half of the time. Tried two different sets of new batteries. Slave mode and the test flash both work off of the camera. Cleaned the cameras shoe and checked that little post, but my camera is quite new so everything looks good.

Ive tried every setting and mode, read both the manuals and searched online for similar problems but cant seem to find anything. I just rented my schools 580exII last week and it worked flawlessly, and I havent used my camera since then. I read somewhere about burning up the circuit in the camera but that wouldnt be the case because it can still fire right? (at least I hope it isnt that ) I just want to be sure its a faulty flash unit before I have to go deal with the morons at best buy. Also I dont have another canon I can test it on.

Sorry that was long winded, Im just really confused and angry haha

Sounds like it might not be locked down correctly? If it isnt that, send it back

The fact that the 580 worked and the 430 works in wireless mode (plus the flickering in the viewfinder) means a hot shoe contact problem. If you can consistently replicate the issue, take the flash and camera to BB and show them the problem. Try another flash in-store and if it works normally they should exchange it.

It was the flash, thank god, thanks for the responses. They took it back no problem. Maybe I can pick up an used 580exII for cheap now that they announced the 600ex

Also not sure how I've gone 2 years on this site without posting, when Im on potn quite a bit. Ive got to stop lurking haha