Engineering Kit R2 - Incorrect Battery connection to the board in the kit

[llxff]

Hi,
want to warn you that the wires of the battery holder mapped incorrectly to the board. The black wire is connected to "-" of the battery and "+" of the board connector. The red wire is connected to "+" of the battery and "-" of the board connector.

Another problem is  that there are no mapping labels on the battery.

Unfortunately, I realised this after connected the battery to the board and the battery started to burn. Now the BAT LED is always on, not sure if it is not damaged. I am absolutely new to the electronics, is it safe to continue use it like this?

[PureRockets]

On mine, the red cable is properly connected to the flat/+ side of the yellow plug. Which is different than the one in your photo. You can check with a voltmeter, I've seen them for less than $5 USD online.