First build

...Spoke to them today to hear that the existing BB was out but because it was cup and cone they were unable to replace to check the threads...
I assume something was lost in translation, because that makes no sense.

You want the BB shell "chased and faced": the threads are "chased" to ensure they are clean and free; the outside of the shell is "faced" so that the surfaces are flat and parallel to each other.

All of this ensures that that the actual BB is easy to fit and functions properly.

I don't understand why they would want refit the current BB nor why they can't do so.