Invisalign rubber bands pulling my retainer up

Hey! Okay so I've been having a lot of issues with Invisalign. I've had to get 2 new set of trays apart from the original set because they messed up with the scan. Now with these new trays the bands are pulling my bottom retainer up so that it's not tight on my teeth. I told my ortho and he said it'll be okay but is he just saying that because we've had to go through two new sets of trays or is it fine?