Can I challenge an ex parte judgment with proof of unavailability?

Hello, my case was decided ex parte. I was in Lucknow at the time, and a one-time summon/notice regarding legal action was sent, which my mother refused to accept, citing my unavailability in the city and her lack of awareness of the consequences. I learned about the case only when I received the judgment by post. Am I eligible to challenge the judgment and apply for a rehearing to present my side of the story? I have proof of my unavailability in the city during the period when the notice was supposed to be delivered. Kindly advice.