Summon to witness

A family member of my friend(residing in amritsar) contacted me on facebook and narrated their family problem. Then he defamed that friend by telling some improper things. He wrote me on facebook and whatsapp and then he called me and said a lot of things. I normally forwarded few chats and wrote those things too which i conversed on telephone. It was a normal chatting i did with my friend and i told the matter. She filed an FIR against her family member. Ehen i was interrogated by the police i said yes this was the truth. Now after four years, i am being summoned by the court as a witness.. I was not in contact with my friend for four years and i didn't even know that a case has been done and my chatting(which i sent to my friend which includes facebook and telephonic conversation) has been used as an evidence. I obviously don't have that chat saved after such a long time.. In the mid of my busy schedule i have to travel a long distance to give me attendance to the court even when i haven't done anything and i was not informed when the case was done 3 years back. I have not been given any travel expenses too.