How should I proceed in case of a payment failure?

You may try alternate payment methods highlighted in the links below in case of a payment failure.

https://www.smergers.com/faq/i-do-not-have-a-paypal-account-can-i-still-use-paypal-gateway-to-pay/260/ 

https://www.smergers.com/faq/how-do-i-pay-using-paypal-gateway/251/

https://www.smergers.com/faq/i-need-smergers-bank-account-details/250/