Does any know if the Relationship Assessment Scale (RAS) is free to use?

Hi! I’m a psychology student who is currently working on my undergraduate thesis and one the standardised tests I plan on using is RAS which will measure relationship satisfaction. Prior to contacting the author, I did some research and did not find if it is free to use or I need to request permission first before using. So I contacted the author via email a month ago but no reply to this day. So I really wanna know if anyone here has used RAS and if it is okay to use for free or there may be another way to contact the author. Please let me know, thank you!