Hi, I'm Arlene, an independent advisor and I'm here to help you, thank you for reaching out to Microsoft Community and sharing the steps you've already taken.
Just to better understand, could you confirm whether the warranty on your Surface keyboard was purchased through Microsoft Complete or a retailer, and do you have proof of purchase or the warranty plan ID?
According to Microsoft’s official Surface warranty and service support page, if your device is still under warranty (especially through Microsoft Complete, which typically includes accidental damage coverage for three years), you should be eligible for a replacement.
Since your service requests are being closed without resolution, I recommend trying the Microsoft Support Virtual Agent on the Surface support page:
https://support.microsoft.com/en-us/surface
Also sign in with your Microsoft account and go directly to Devices to check your registered Surface and initiate a replacement claim from there. Additionally, calling Microsoft Support directly or reaching out via the Microsoft Store where you purchased the device can sometimes escalate the issue faster when digital requests stall.
Hope it helps. Please let me know if you have further question.
Regards,
Arlene D.