Nothing about that is clear without knowing the relevant laws of wherever this is, the contract, the circumstances of development, and who knows what else. This is why legal advice from random internet strangers is a bad idea.
> There should be no lawyer involved with this cause it’s not a legal negotiation.
The very first thing you should learn about negotiation is that you never walk into any negotiation until you know your BATNA. How do you know your BATNA in a situation like this? You talk to a lawyer!
It’s pretty clear you have no legal position.
But you are the key player in the project.
So negotiate. Decide what you could get out of it and ask for it.
There should be no lawyer involved with this cause it’s not a legal negotiation.