We attached conditional waivers to all billings. The retention bill was submitted with a Final Conditional Waiver (without exceptions) and paid. However, we have an unpaid progress bill that was previously submitted with a Progress Conditional Waiver. Our customer is claiming that payment for retention, which matched the amount on the Final Conditional Waiver, replaces all previous Progress Conditional Waivers and they are refusing to pay us. Is the Progress Conditional Waiver for the unpaid bill still enforceable?