my medela freestyle pump is showing the error message "BATT" while charging. I've already removed the battery and re started the charging process but the error message is still showing. any tips how to reset this?

Do charge it for a few hours to check if the battery is live. If the problem persists, you might need a new battery. You can send the pump for servicing if your warranty is still valid at the service centre. Try not to use it while it is still charging. It could also be due to a faulty adaptor which produces this error message too. You can borrow a Medela adaptor from a friend to test this out too.