I had a series of EIGHT bad tubes from the LBS a few years ago, all the while the salesguy said they have had no other complaints. I kept bringing them back and they replaced them all 8 times. When I went back with the last one to get a refund and THIS NEW salesguy says they have about 20 or 30 of them to send back. So I was not alone.

First, dismount the wheel, deflate the tube (in the case it still has any air left) and then pull one side of the tire off. Mark an X on the rim AND tube to the left or right of the valve stem with a marker. Then pull out the tube and inspect it. Look for the failure, since it was so sudden and catastrophic it should be obvious. If it's not then fill it with air partially and listen for leaks or dunk it in a bucket of water to see the leak. Lay it back on the rim and take note of where the leak is on the tire.

Once you find out WHERE the tube is leaking then find out WHY it's leaking. Line up the failed spot using the X and the stem as reference. Thoroughly inspect the rim and the tire in that area for sharps, edges or tiny wires. I once had to get a few cotton balls and carefully drag them around the inside of the tire, the cotton snagged on a nearly microscopic wire that I could barely feel with my finger. It took me wearing magnifying glasses under a bright light using tweezers to remove it.

I would go to a DIFFERENT LBS or order new tubes online. I order Michelin Air-Stop tubes and have had good luck with them.

In the case of my 8 blown tubes it appears that the valve stem ring - the transition from the valve stem to the tube itself was not cured properly and all the tubes popped, so be on the lookout for that too.