I am involved in a contract dispute, basis as follows;Client signs contract and pays 5% non refundable deposit £18k.

I am involved in a contract dispute, basis as follows;

Client signs contract and pays 5% non refundable deposit £18k.

Client pays further £37k as per agreed contract payment structure.

Via solicitor client terminates contract demanding all funds returned or action raised.

I make offer to return £37k in full and final settlement.

Client offers to accept £45k in full and final settlement.

I again offer to return £37k in full NBC and final settlement 

Client offers to accept £42k in full and final settlement.

Should I return £37k with note saying that I have no intention of returning any further money?