My asus Rog Phone 2 power and volume up button become mushy

Please tell us some basic information before asking for help:

1. Model Name: Asus Rog Phone 2
2. Firmware Version:
3. Rooted or not: Not
4. Frequency of Occurrence: Always
5. APP Name & APP Version (If your issue relates to the app):

In addition to information above, please also provide as much details as you can, e.g., using scenario, what troubleshooting you've already done, screenshot, etc.

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Its been 9 months i purchased this phone..........everything was working fine until yesterday.. all of a sudden first the volume up button lost its clickiness and then after power button also lost its clickiness and became mushy.....both of those buttons just went inside their grooves but not popping up as usual...... although they are working with slight pressure but the ply is not there.....Currently i am using a third party app for locking my screen and double tap to wake it up. Please let me know what i should I do and if this is covered in warranty or not.....in the past 9 months i havent dropped my phone even once also and also there is not even a single scratch on my phone. I dont know why all of a sudden those buttons became mushy. PLease do respond as soon as possible....