Ordered a 4XL - I'm 165 lbs., 5'6", DDD bust.  The suit fit around my butt and waist, but was too small on the top and barely covered my breasts.
Also, the suit is lined in the front, but not in the back.  The fabric is very thin and transparent, so it will be see-through, which isn't really what I'm going for in a bathing suit.

I contacted the seller to return it, and they advised that they can only refund 70% of the purchase price.

Don't bother.