Tech: Please call and ask for this exact thing to be done. Here is what you should say. They will know what to do.
User: Help Desk, I was told to call you by a tech.
Service Desk: Is that all the tech said?
Service Desk: (liar…I spoke with the tech already…he told you to tell me to rebuild your OST) Can you read me exactly what the tech said?
User: Service Desk, please rebuild the OST.
Service Desk: Thank you. I know exactly what to do for you.
User: (surprise in their voice) You do?
Service Desk: Yes. (Imagining packing their computer in a box, and handing them a pen, paper, and postage stamp.)