Geberit India — continuous leak of water even after the flushing is done

Address:

641111

I have been using geberit for more than two years, never had any problems until lately. If i flush, the flushing is done but the water from inside the tank doesn't stop completely. It leaks slowly and continuously make my water tank completely empty if not noticed. So for now i have stopped using the toilet and closed the water line tho the toilet, which is very inconvenient for my kids and parents.
I would please ask you to repair this issue as fast as possible to lessen the discomfort we are experiencing