I think I know what you’re talking about but I don’t think they’re “balloons” that fill with air necessarily. Pretty sure the rubber-like material is molded in that shape. You can try to get those cup holder inserts out (idk if they come out), or try to disassemble the cup holders and push it back out from inside, or try using a pin to pry it back to make it pop back to form, or if none of that works maybe somehow something physically altered it. Maybe an extremely hot drink deformed it? I would think it would need to be like boiling hot for that to even be a possibility though! Just thought I’d give some suggestions though, good luck!