B1/B2 interview waiver and passport issue

I have applied for a USA B1/B2 visa for the first time. I have submitted my passport with the required documents to the USA embassy in Vancouver, BC. On February 7th, 2024, they received my passport with the documents at their embassy. I received a message from the processor stating that I need to submit my old passport, which has a B1/B2 visa stamped on it. However, I have never had a B1/B2 visa or any other USA visa before. It has been a month since I tried contacting customer service, but they were not helpful and could not answer my questions. I hope you understand my query. Thank you for your support. Please Help.