The OpenCage Geocoding API is being misused by users who were recommended by ChatGPT to use the API for reverse phone number lookup, a service that OpenCage does not provide. This has led to frustrated users and increased support requests for OpenCage. The issue is attributed to ChatGPT's training on faulty YouTube tutorials and its ability to generate convincing but false information. OpenCage is warning users not to trust ChatGPT's output as truthful.