Client does not answer

[b0f24c19]

We have agreed a job as 2 milestones with my client who is payment verified and spend over 50k dollars. First milestone was basic model and render and second milestone was final model. It was 3 days job. First milestone was done in 14 hours and client was very happy and he payed me first milestone. But the problem is first milestone was basic model and i did more than basic model i basically almost finished the job since i felt not comfortable to deliver basic model. He said he will talk with his partners and tell me if there will be change. And ever since he does not even respond my messages for 3 weeks. If he dont want any changes i should get my final payment because it is done, but i cannot demand money because maybe he can give me bad review just because this and it is very important for me. I'm not sure how can you help me but i assume there could be some protection for situations like this.