Firstly, check the Micro USB cable with another device if possible. If this other device doesn't charge, this would point to an issue with the cable or the charging port, so try an alternative. You might also want to try another IMR battery to see if the issue is with the battery rather than the SERIES-B Tilt.
If no other battery is available, try another Micro USB cable. If the issue does lie with the SERIES-B Tilt and not the cable, please do contact our customer services team who will arrange a replacement if the SERIES-B Tilt is within its warranty period.