KDR - Builder asking more money to walk out - please help

Due to conflicts with builder (mainly due to $100k price rise, poor communication, extremely throughout) we have decided to change the builder.
We are very happy finally we are moving out with confidence.
But we have paid $16k and now they are asking us to pay $6k more.
DA plan is approved and we have paid that $2.5k fees separately.
Construction certificate is not yet applied.

We are shocked by this additional $6k from builder.
So as soon as this is paid they will collaborate our file, have all plans updated without company branding and send to us a final release letter

My questions are - What should I do in this case? I am afraid if I decline or negotiate this $6k they may block some paper works for us.




Thanks for your valuable inputs.

 

The $6k is for engineering to the CC & admin fees.

You would be paying for it regardless

 

Thank you for your response.

But CC is not even submitted
Plus what they have charged us $21k for , instead of additional 6k payment, we were thinking we might get some % back from 21k

Even if I proceed with this 6k payment, what all documents I should get from them so the new builder would have no issue in taking our job.