Petland has sold me a mixed breed shih tzu at shih tzu price how do i find out what kinda dog he really is?

Instead of leaving deposit on the liver colored shih tzu I paid n full n was told id have to return n two days to pick him up well win I returned he was blonde and bigger alspi was then told he is neutered.sighing...I've been bamboozled.while his papers say liver colored n his chip says liver colored he is blonde and his face is not broad hs eyes aren't bighes not a purebreed.please help or advise me please