hi i managed to purchase the battery and replace it via Ali Express website. Search for battery size 302530 3.7v 300 mah Lithium . Thickness 3mm, width 25mm, length 30mm.

Take note when you replace the battery the wire that comes with the new battery wire will be too thick to insert into the mini small white clip. What i did was to cut off the old wire from the old battery and connect it with the new battery wire.