Yes, Monsanto developed the terminator gene technology.
They have never used it in their products.
Yes, Monsanto enforces their contract that prohibits seed saving by farmers. If farmers want to use seed saved from harvest for the next year's crop, they have to use some other source for their initial seed. Most US and European farmers were already buying seed every year before GMO seed became available. This was less common with soybeans, but the trend was there.
NPR report on the Top Five Myths Of Genetically Modified Seeds.