Red Carpet — credit card

Address:	Third Floor, Balraj Building, 100-feet road, Ghitorni Metro Station, New Delhi - 110030, New Delhi, Delhi, 110030
Website:	www.redcarpetup.com

I have taken credit card from this company, I lost full access to my sim card because I didn't recharge. Now I want to pay online my bill and the OTP goes to the old number.
I have been calling from one week requesting them to change the given number. But they are telling they want some NSC certificate which Docomo says they don't provide.
Later when I told them that, they are asking me to send an email ... And there's no reply and I have to urgently pay my bill...
So please consider making this quickly