blossom chevrolet doing the same work everyother time that i take the car in for repair indianapolis, Indiana

When I took my 2006 Chevy the dealership for my second oil change, they informed me that I had a CV joint that was licking and a lick around the oil pan. They did this work on warrenty. Two oil changes later they did this some work again on warrenty. Now less than tree thousand miles later I get a notice that I still have this same problem with my 2006 chevy. I know that if the work is done right it will not come undone in that short of time. They think that I done know what they are doing. Help me get this work done right.