You're employer has already refused to modify the contract. What makes you think getting advice here is going to give you any ammunition.

It won't.

You're right, you have the option of declining the position or accepting with the contract as is and commit to the 3 years.

All I can suggest is that you have an attorney review the contract and advise you on it. With $20,000 at risk, you can certainly afford a few hundred worth of an attorney's time.