Stingray Digital Group Inc. has responded to a patent infringement lawsuit filed by competitor Music Choice and filed its own suit against Music Choice alleging illegal business activities. In June, Music Choice, a Pennsylvania-based multi-platform video and music network, filed a complaint for patent infringement against the Montreal-based company. In court documents Tuesday, Stingray, which had already called Music Choice’s complaint “not material,” formally denied the allegations and filed counterclaims of “non-infringement and invalidity of the five...