I completed the course but it only shows 50% complete.

You must go through each slide, and/or click on all interactive portions of the course, for it to show complete. Try going through the course again, to make sure this was done. Keep in mind there may be two parts to the course. The course itself, and a test/quiz that may be associated. In this case, the course may show 50% complete, if you have only completed the course portion. You would also need to complete the test/quiz, for the course to show 100% completion.