It doesn't sound like they negotiated an exclusive license to the technology in the initial contract. If that's what they want, they should pay for it. Assumi

It doesn't sound like they negotiated an exclusive license to the technology in the initial contract. If that's what they want, they should pay for it. Assuming the value of your work is now proven, I think you should work that angle. "You see how valuable this is; wouldn't you like to have exclusive rights to it?" The price should go up by at least 10x.