Revolution Slider

I bought a theme and i am required to install slider revolution plugin but every time i tried it fails to install and tells me it needs newer version which is v6.5.8 .
i tried to download direct from wordpress but its not working there and when i come to envato they are selling it for 85 dollars. what do you think i can do

Hi,

Contact with your purchase item author hope they will helped!
https://help.market.envato.com/hc/en-us/articles/203039054-How-to-contact-an-author

Thanks!