Hi JudeEsangbedo,
Thank you for reaching out to Microsoft Community.
Does the LED on the mouse still blinks when you tried to pair it? Try pressing and holding down the pairing button at the bottom of the mouse until the LED starts to flash (mouse will be in pairing mode). Please see this page for details: Set up Surface Mobile mouse.
If the LED does not light up/blink anymore, please try replacing the battery of the mouse then pair it again.
If this answer your question, we highly encourage you to inform our Community by clicking on Yes or marking my post as an answer. This will help other members who may have the same issue as you. Otherwise, don't hesitate to update us so we can further assist you.
Kind Regards,
Marrion Y.