We have a general contractor we did work for. I have sent in all the payment paperwork requested, but never received the first payment. We completed the job in March '22. They sent through the request for the paperwork for the retainer and I sent it with a conditional waiver. They don't want to release the checks to us until I send an unconditional, but I'm hesitant to do so since they have a history of withholding payment for long periods of time. How should I proceed?