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Give me a moment, I will help you in fixing it.
What is the name of your device ?
I think you would need to reset your boot setting as now your keyboard and mouse in not working even in BIOS . You will have to clear CMOS to reset BIOS to default. As you have recently purchased this device you can contact its vendor and ask them to restore dual OS for you. Your product is under warranty and I won't suggest you to do anything which can void it warranty.
Yes you can ask for your refund, for that you will have to contact customer service team.
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