• Authenticity check of Emails on Yahoo Web site

A dealer purchased some material from our company for its various customers as per different purchase orders. He followed payment schedule as per agreement but after some months he started delaying payment and did not make the payment as per the payment terms and thus a huge payment accumulated. We requested him many times to follow payment terms but he did not follow the payment schedule as a result we had to stop the material supplies to him by giving him notice in writing till he does not clear balance payment as well as amending the agreement regarding his permitted working area. After we had stopped the supply then he purchased some material in cash also. After some months of stopping of supplies without making any payment he filed a suit/case against us saying that quality was very poor and because of this his customers suffered financially and his all made payments be returned while he continued to purchase for 2.75 years and warranty of more than 83% material had already finished and 92% warrantee of first-time supplied material against all purchase orders also had finished. He has shown too many emails after we stopped the supply by giving him notice in writing in the period of 2.75 years while he was purchasing the material plus in next 1 more year after stoppage of supplies to him and when he had filed the suite. Emails being actually written to us were less than 10 % of the total emails being shown as sent. While these 10 % emails were regarding material purchase, supply, installation etc.
After studying and checking these e-mails we found that 80% email which he has shown in this case in the court are fake which were never sent .On our compliant regarding this Court has ask him to bring his Laptop to check out the truth of his claim as well as asked us to file PF to call the Yahoo (These emails are being shown as sent on our Yahoo e-mail id) .We filed PF with list of all emails being shown as sent to us and also indicated those emails which we did not receive. Here I want to know whether Emails can be manipulated on the laptop or computer and can be shown as being sent while actually were not being sent. I want to know further whether the Yahoo is bound to come as per our PF notice being sent to its office as he is using these fake emails to cheat us for big money. And I want to know what the further way is to counter this type of cheating tactics. I also want to know further whether courts in Delhi have some soft content expert which may check authenticity of these emails by finding whether these were actually sent or just being shown as sent through some cheating method. Is court capable of checking authenticity of the emails on opposite party`s laptop if Yahoo personnel does not come to the court and court does not have its own expert and can the ask this opp. Party to check these emails. So, please advise me what is the correct way to counter this cheating technique.