Did you let them rest for 12-24hrs pointy side down before popping them in the incubator? This is to help the air cells settle and hopefully stabilize. Not a huge problem if you didn’t but I’d still want them vertical with the air cells end up. Some recommend keeping them vertical for the first few days and then doing horizontal if you have a horizontal turner.
I am not super experienced with shipped eggs, only tried it 5 times. I’ve decided vertical incubation is better but I have a horizontal incubator so I removed the rollers and placed the eggs in cartons, fat side up. I turned them by tilting the entire incubator this way or that several times a day while using a small box to prop up the bator. Worked okay but my best successes was with a batch of eggs that only had to travel a state or two away. Of course packaging and time in the mail plays a huge role as well.