Dear applicant the most important fact at this moment would be to pay the desired money, because whatever money you paid you will get the refund within 7 working days. If you have tried to make the payment through UPI mode then try to make the payment through Debit Cards ( RuPay, MasterCard or Visa) or Credit Cards as well. You can contact the enquiry mail id of the Bank or the Contact details provided by the examination authority regarding payment stating your issue. But try to make an alternate successful payment within the deadline to avoid further issues,

Hope it helps!!