I really don't understand how can people comment "it should work" without trying themselves first. The truth is, majority of online merchants do not support international Visa and Master Card in India due to high MDR and other headaches. Not to mention that international transactions are minuscule so as to be insignificant.
To answer the OP, you can use an international recharge website which recharges any number. My recommendation is
Send Mobile Top-Up. Online Recharge for Prepaid Cellphones - ezetop.com. They also charge commission FYI.