Magic Mouse will not keep a charge

So I have run into a unique issue that I need help solving, my magic mouse will not charge, I have tried cleaning the port and testing the charging cable, the cable is brand new and works but I have discovered that isn't the issue. The mouse is stuck at 4% battery, when i connect my mouse to my mac to charge, it will give the info that it is charging and the percentage on the battery will go up, but the second I unplug the mouse and plug it back in again it drops back down to 4% and will start charging again. It has sat charging for hours and no matter how high it says the battery is, it will still drop down to 4% the second it is unplugged, I have tested this several times and I don't know what is going on or how to fix it, please help!