There is a concept of "Eid echad ne'eman b'issurin" which means if a person testifies on something that is questionable we believe him. An example would be regarding kosher: if I go to a friend's ...
Is there an issue of publicly protesting a Jewish business, such as by picketing or boycotting, being a chilul Hashem? Are there any other (halachic or other) problems? What if you believe that the ...