I write to dispute your claim in its entirety. Your claim cannot be justified at this time.
You had never notified me for this repair, therefore, I am not liable for your claimed costs. However, I am offering my good faith to research this matter but I am herein requesting a detailed cost breakdown including not limited to Material costs, labor hourly rate(s), time on the job, and any other costs included in your claim. Requesting this cost breakdown is not an explicit nor implicit admission.
Please consider this letter as a cease and desist demand. Any future communication must be in writing.
Please govern yourself.