Wrong credit for David Campbell

David Campbell from 'Scarecrows', 'Killer Workout', 'Deadly Prey' and many other movies wasn't in that movie. The guy named Grime in the movie is some other David Campbell, much younger.

Same with other movie by Damian Lee 'Killing Machine'. I bought these two just because I tought David will be there but he wasn't. This other guy don't even exists on imdb.

Probably all these karate things have wrong credit and David wasn't acting in any of them.