Prepare one device list
Add the model, user and symptom. For several devices, send one list with the condition of each unit.
Protect data and access
Back up when possible and never send passwords, access codes or sensitive data by message. If a device will not start, record what happened before failure.
Name the contact person
Choose who can answer questions, approve the work and provide billing details.
Send the device details
Include models, quantities and symptoms. Ask for the cost and estimated timing before approving work.