Are you lubing the inside of the case Neck? You could dedicate a nylon case neck brush to appling some lube, that has worked well for me when less complete methods of lubing the neck are giving marginal results.

There are kits for removing stuck cases. Basically, you drill out the base, tap it, and then use your press to pull it out. Takes a little time, but not as long as UPS.

Also, check your shell holder. Make sure you have the correct one, and it has not been damaged.