Hey houmanshahi,
Thanks for reaching out to us! We typically take the weekends off from support, I apologize for any inconvenience or delays that this has caused.
I took a look at your site and it appears that there is a purchase option being displayed on the event page https://cloudup.com/cvPBPC58zKW. Did you have multiple tickets for this event that displayed at the bottom of the page similar to https://theeventscalendar.com/content/uploads/2013/02/woo-frontend-e1420243552702.png that are now missing?
If so, check the sale dates on the tickets within the event settings and ensure that there isn’t an “end sale” date added for the ticket that has already passed.
Let me know if this helps.
Thanks!