Hathway Cable & Datacom — showing negative balance in cart

Address:

Bangalore, Karnataka, 560037

Hi,
I have a cable tv connection from hathway.
Account number: [protected]
There is negative balance of 906. Not sure why this amount is being shown in the app.
I have made the bills correctly when it was post paid.
Recently I had added 2 kids channel in mid march and during this the cart was showing the amount correctly. Now when I trying to recharge in April month its by default showing 906 Rupees.
I had called customer care of hathway and raised a complaint on 10th April. From then on I have been calling customer care everyday twice and they keep saying billing team will get back. But after a week also hathway is not able to give an answer for why I m being charged 906. They have the worst customer care support. Please help me in getting this addressed ASAP.

Thanks,
MokshaKS