Can i order from Amazon Prime on Wednesday, when there is guaranteed delivery on shabbos? Does it fall into the issur of amira l’okum to have a goy to a melocho for me on shabbos?,
If the delivery is specifically for Shabbos this would be prohibited, and included in the prohibition of Amira LAkum.
However, if the agreement is that it must be there by Shabbos, but they can also deliver it before Shabbos, and this is a possibility for them, it would be permitted. In that case they are delivering it on Shabbos for their own convenience.