I wonder if the archery shop didn't place one of the string loops over one of the feed posts to change the draw. Looking at the cable side of the Infinity can you should be able to read the number and letter of the module on the cam. You will notice that there are 3 individual posts togther and one joined pair of posts. The string loop should not be over any of these posts and should be over the single post nearest to or slightly under the limb. Also check to see if the module screws are tight and the module is installed correctly.