Yeah, I know what your talking about.
I just got done beating a Wolf B spammer... it's not that easy.
What you can try doing is backing off of the distance of the Shot and wait for him too near you.
Then, when he does that's when you get a little closer too him and jump between his shots and attack from the air when you get the chance.
But be careful cause wolf can easily counter with his fast up B moves and such..
But if you are able to land the hit, you need to stay one step ahead of him and just hammer away with attacks. Dont give him time to breathe or recover and get that distance again.
There's really no offical way to beat them.. all i can say is minimize distance.
If all fails..
Turn to The Great Falchion for help!!
I kicked wolf's *** with my Marth!!