Bathtub spout leaks

Hi,
I had a shower faucet and tub spout replaced. When I turned the faucet on in order for the water to come out of the tub faucet, the water not only came out of the spout, but it was leaking from the part of the spout where it meets the wall. It leaks on the bottom. This is a single handle faucet. What is the problem. thanks.

There are two kinds of tub spouts: Ones that slip on and have a set screw, and ones that screw on. If it is a slip-on, you can use an allen wrench to tighten the set screw. If it is a screw-on, you can unscrew it and add some teflon tape to the threads of the stub-out.