Please note that it is essential to disconnect the Google account from your device before sending it to be repaired. If the Google account is still active on the device it will be impossible for the repair team to open the phone settings and the test menu.
This short guide will show you step by step the procedure to take in order to disconnect the account. 😊 You can find all the information, about the steps to follow before sending back your device, in this article: What should I do before returning my device/order?