Question

why we cannot refuse to accept payment in rupee

Answer 1

This statute means that all United States money as identified above are a valid and legal offer of payment for debts when tendered to a creditor. There is, however, no Federal statute mandating that a private business, a person or an organization must accept currency or coins as for payment for goods and/or services.

Answer 2

because the rupee is issued by the reserve bank of India and we can't refuse to them