I’d suggest contacting Microsoft directly through the Contact Us page: support.microsoft.com/contactus. Sign in with your Microsoft account, select Devices → Surface, and choose Chat or Request a call instead of going through the self-help options. That usually gives you a better chance of reaching a live support agent, whereas the Get Help app can sometimes keep sending you through automated troubleshooting.
If that doesn’t work, you can also try Microsoft’s Global Customer Service phone numbers and call them directly. Select Surface, then Home when prompted. The IVR may mention Business, but the line also handles Home users.
Another option is @MicrosoftHelps on X (Twitter). Their support team monitors the account, and they can sometimes connect you with a human agent when you’re stuck in the automated support loop.
Regarding data destruction: since you’ve already factory-reset the device and removed your personal data yourself, that is generally sufficient for Microsoft’s process. For a consumer out-of-warranty replacement, Microsoft normally doesn’t return the original device or provide a separate certificate of destruction. The device goes through Microsoft’s own refurbishment or disposal process.
If you specifically need an official certificate confirming data destruction, ask the support agent about the Business/Education repair process, as that may have different documentation options. Since you’re a student, it’s worth explaining your situation and asking whether they can provide any equivalent confirmation for your case.