Boarderguy
Chief Narctopus Wrangler
I ordered mine separately trying to avoid tarrifs and had to input my numbers since it was a different order. I'm special thoughUnless he did something weird, he would have given Seaskin one set of numbers, which they use for making the suit and the undies. So, if the suit itself fits correctly, that kind of confirms the #s are good.
It sounds like they just screwed up when making the undersuit.
Perhaps ask them for a few reference measurements of what the undersuit SHOULD be, and check it yourself (@Deezer-D).