If the breeder said there's an "injection" of another breed I'd definitely think she was a mix and has something besides what makes a yorkie in her dna, but since the breeder is already giving you the $$$ back I wouldn't worry about DNA(since he/she pretty much already admitted she's a mix)unless it's for fun
. Definitely agree with the home remedies...I have a Cuban MIL who swears by cayenne pepper and it really does work lol. But either way your new pup is a cutie!